The lower core layer 7 is formed in approximately constant thickness at the portion confronting the upper core layer so that its thickness gradually reduces toward its side edge. Therefore, the thickness of the layer of the non-magnetic material 8 formed on the lower core layer 7 becomes uniform, stabilizing the coil layer formed thereon. An excellent material of soft magnetic materials can be used since the lower core layer 7 is formed by sputtering, enabling to record at a high frequency.

1. Field of the Invention
This invention relates to an inductive type thin film magnetic head for recording with a combination read/write thin film magnetic head that is used for a floating type magnetic head, especially to a combination read/write thin film magnetic head in which a lower core layer serving also as an upper shielding for a readout magnetoresistive element and a coil layer formed on the lower core layer via an insulating layer can be constantly formed, and which allows an improvement in selectivity of soft magnetic materials by forming the lower core layer by a spattering method, and a method for manufacturing the same.
2. Description of the Related Art
FIG. 5 is an enlarged sectional view of a conventional combination read/write thin film magnetic head viewed along the opposite direction of the recording medium.
The layer of the magnetoresistive element 1 is composed of three layers, laminating a soft magnetic layer (a soft adjacent layer; SAL), non-magnetic layer (a SHUNT layer) and a magnetoresistive layer (a MR layer) from the lower to the upper, respectively. Usually, the magnetoresistive layer (MR layer) is a layer of Fe--Ni alloy (permalloy) and the non-magnetic layer (SHUNT layer) is a layer of tantalum (Ta), and the soft magnetic layer is formed with a Ni--Fe--Nb alloy.
A lower gap layer 3 comprising a non-magnetic material like aluminum oxide (Al.sub.2 O.sub.3) is formed on the lower shielding layer 2 composed of sendust or permalloy as shown on the figure, on which a layer of the magnetoresistive layer 1 is formed. Hard bias layers 4 are formed as longitudinal bias layers at both sides of the magnetoresistive layer 1. A main lead layer 5 comprising non-magnetic electrically conductive materials like copper (Cu) or tungsten (W) is formed on the hard bias layer 4 described above. An upper gap layer 6 of a non-magnetic material like aluminum oxide (Al.sub.2 O.sub.3) is further formed on the main lead layer, forming a buffer layer (not shown) on the upper gap layer 6 described above. The buffer layer described above can be formed by sputtering magnetic materials like Fe--Ni alloy (permalloy). A lower core layer 13 is formed on the lower layer described above by plating, for example, permalloy.
A non-magnetic layer 14 comprising aluminum oxide is formed on the lower core layer 13, on which a coil layer 9 formed in a flat spiral pattern is provided via an organic insulating layer. An upper core layer 10 is formed on a layer of non-magnetic material 14 at a position confronting the lower core layer 13. This upper core layer 10 is also formed by plating permalloy as in the lower core layer 13 described above. A protecting layer 11 comprising aluminum oxide is provided on the upper core layer 10.
The layers from the lower core layer 13 to the protective layer 11 serve for signal recording, composing an inductive head. In this inductive head, a recording current is applied to the coil layer 9 so that a recording magnetic field is imparted to the layers from the coil layer 9 to the upper core layer 10 and to the lower core layer 13. Magnetic signals can be recorded on a recording medium like a hard disk by a fringing magnetic filed between the lower core layer 13 and upper core layer 10. In the combination read/write thin film magnetic head in which a read out part with a layer of the magnetoresistive element 1 and inductive head described above are laminated, the lower core layer 13 composing an inductive head also serves as an upper shielding layer in the read out part having a layer of the magnetoresistive element 1 as shown in FIG. 5.
In the inductive head described above, it is required for a high density recording in a recording medium that the gap distance of the magnetic gap G described above should be as short as possible. Therefore, the layer of the non-magnetic material 14 is formed as thin as possible.
In the prior art as shown in FIG. 5, however, there were problems as describe below because the lower core had been formed by plating, for example, permalloy.
(A) A terrace A is formed at both edges of the lower core layer 13 because the lower core layer 13 is thick and the cross sectional configuration of the lower core layer 13 assumes a rectangle. Therefore, making the thickness of the non-magnetic material 14 formed on the lower core layer 13 uniform is so difficult that the thickness of the non-magnetic material 14 becomes extremely thin in the vicinity of the side edges of the lower core layer 13, sometimes causing a failure of electric insulation between the lower core layer 13 and coil layer 9. Especially, when the clearance between the lower core layer 13 and upper core layer 10 is narrowed for making the gap width small in order to increase the recording density, pin holes are liable to appear on the non-magnetic material 14 at the terrace A described above because the thickness of the non-magnetic material 14 becomes too thin.
(B) A terrace is also formed on the surface of the non-magnetic material 14 above the terrace A because the cross sectional configuration of the lower core layer 13 is a rectangle forming a terrace A at both side edges. Therefore, the coil layer 9 is formed on the terrace of the non-magnetic material 14 when the area of the lower core layer 13 is smaller than the area where the coil layer 9 is formed, thereby making it difficult to form the coil layer 9 and resulting in a frequent appearance of defects in the coil layer 9.
(C) For the purpose of increasing the signal recording density and magnetic recording frequency in recording media, it is required to improve the soft magnetic characteristic of the lower core layer 13 and upper core layer 10 as well as to make them to have such properties as low coercive force and high resistivity at high saturated magnetic flux density. Permalloy that has been the conventional material for forming the lower core layer 13 and upper core layer 10 is not always a satisfactory magnetic material because, although its saturated magnetic flux density is high, its coercive force is relatively high and resistivity is relatively low so that, when the recording frequency is made higher, it results in an increase of eddy current loss and deterioration of soft magnetic characteristic. Meanwhile, U.S. Pat. No. 5,573,863 discloses a soft magnetic material in which a microcrystalline phase of Fe with a bcc crystal structure, and an amorphous phase containing the elements selected from rare earth elements or from Ti, Zr, Hf, V, Nb, Ta and W, and O, are mixed together. This kind of soft magnetic material has a high magnetic permeability at a frequency of hundreds MHz or more as well as a high saturated magnetic flux density of 5 kg or more besides having a high resistivity at low coercive force. It is preferable in the future-coming inductive head for the purpose of high density recording that the lower core layer 13 and upper core layer 10 is formed using such materials excellent in the soft magnetic characteristic as hitherto described. However, the soft magnetic material as described in the afore mentioned U.S. Pat. No. 5,573,863 in which a microcrystalline phase of Fe and amorphous phase comprising metal elements and O are mixed together can not be formed by plating, instead a sputtering method or an evaporation method is only applicable for forming the layers. In the combination read/write thin film magnetic head having a construction as shown in FIG. 5, however, forming the lower core layer 13 by sputtering was so difficult that only a material like permalloy that is adaptable for plating can be used for the soft magnetic material of the lower core layer 13.
The above description will be elaborated hereinafter. When the lower core layer 13 is formed by a sputtering method, a layer of a soft magnetic material is directly formed on the upper gap layer 6 comprising aluminum oxide on the layer of a magnetoresistive element 1. However, it is necessary to eliminate the excess part by an ion milling (dry etching) method for forming the lower core layer 13 into a prescribed configuration as described above after forming a layer of soft magnetic material by a sputtering method. It is a problem that the underlying layer of aluminum oxide is damaged when the layer of soft magnetic material is eliminated by ion milling. Generally speaking, a tolerance of about 5% in the thickness of layers to be eliminated is inevitable when a prescribed thickness of layers are eliminated by the ion milling method. Since the thickness of the underlying upper gap layer 6 is smaller than the thickness of the lower core layer 13, the thin upper gap layer 6 is liable to be damaged due to an error of about 5% in the thickness of layers to be eliminated when the upper gap layer 6 is formed by eliminating a part of the layer of soft magnetic materials formed by sputtering. In addition, since the velocity of milling is slower in the soft magnetic material comprising the lower core layer 13 than in aluminum oxide comprising the upper gap layer 6, the latter is far more liable to be damaged when the layer of the soft magnetic material is eliminated by ion milling.
The gap width of the reading part by the layer of the magnetoresistive element 1 is determined by the thickness of the lower gap layer 3 and upper gap layer 6 in this thin film magnetic head. Therefore, the upper gap layer 6 should be thin in order to enhance the resolution against high density signals. When the upper gap layer 6 is made thin in the thin film magnetic head for enabling readout of the high density signals, the upper gap layer 6 is liable to be largely damaged due to the error in the thickness for eliminating layers by the ion milling and milling rate.
From the discussions above, it can be concluded that the materials having an excellent soft magnetic characteristic as described in U.S. Pat. No. 5,573,863 can not be used in the inductive head, wherein the upper gap layer 6 is disposed on the layer of the magnetoresistive element 1 on which the lower core layer 13 is further formed and the lower core layer 13 also serves as a shield layer of the layer of the magnetoresistive element 1 as shown in FIG. 5, since the lower core layer 13 can be formed only by a plating process, thereby narrowing the selection range for the soft magnetic materials to be used for forming the lower core layer 13.

Combination read/write thin film magnetic head


The invention provides a process for quenching free radicals present in irradiated ultrahigh molecular weight polyethylene comprising the steps of (a) providing a mass of irradiated ultrahigh molecular weight polyethylene, wherein the mass comprises free radicals, (b) immersing at least a portion of the mass of irradiated ultrahigh molecular weight polyethylene in a non-polar solvent having a temperature for a time and under conditions sufficient to quench a substantial portion of the free radicals contained therein, wherein the temperature of the non-polar solvent is maintained below the melting point of the ultrahigh molecular weight polyethylene, (c) removing the mass of irradiated ultrahigh molecular weight polyethylene from the non-polar solvent, and (d) removing any non-polar solvent from the mass of irradiated ultrahigh molecular weight polyethylene.

Ultrahigh molecular weight polyethylene ("UHMWPE") is commonly used in making orthopaedic implants, such as artificial hip joints. In recent years, it has become increasingly apparent that tissue necrosis and osteolysis at the interface of the orthopaedic implant and the host bone are primary contributors to the long-term loosening failure of prosthetic joints. It is generally accepted by orthopaedic surgeons and biomaterials scientists that this tissue necrosis and osteolysis is due, at least in part, to the presence of microscopic particles of UHMWPE produced during the wear of the UHMWPE components. The reaction of the body to these particles includes inflammation and deterioration of the tissues, particularly the bone to which the orthopaedic implant is anchored. Eventually, the orthopaedic implant becomes painfully loose and must be revised.
In order to increase the useful life of orthopaedic implants having UHMWPE parts, several attempts have been made to increase the wear resistance of the UHMWPE, thereby decreasing the number of wear particles that can cause tissue necrosis and/or osteolysis. One method for increasing the wear resistance of UHMWPE utilizes exposure to high-energy radiation, such as gamma radiation, in an inert or reduced-pressure atmosphere to induce cross-linking between the polyethylene molecules. This cross-linking creates a three-dimensional network of polyethylene molecules within the polymer which renders it more resistant to wear, such as adhesive wear. However, the free radicals formed upon irradiation of UHMWPE can also participate in oxidation reactions which reduce the molecular weight of the polymer via chain scission, leading to degradation of mechanical properties, embrittlement, and a significant increase in wear rate. These free radicals are very long-lived (greater than eight years), so that oxidation can continue over a very long period of time resulting in as much as a 5-fold increase in the wear rate as a result of oxidation over a period of about 5 years. Therefore, the long term wear resistance of irradiated UHMWPE, and the useful life of an orthopaedic implant having irradiated UHMWPE parts, substantially depends upon reducing the number of free radicals present in the UHMWPE before it is exposed to an oxidizing environment, such as air or the oxygen-rich in vivo environment.
There are several processes that have been developed to effectively and efficiently reduce the number of free radicals present in irradiated UHMWPE, all of which have met with varying degrees of success. For example, U.S. Pat. No. 5,414,049 discloses a process in which an irradiated formed implant of UHMWPE is heated to a temperature between 37° C. and the melting point of the UHMWPE in an oxygen-reduced, non-reactive atmosphere for a length of time sufficient to reduce the number of free radicals present in the UHMWPE. The disclosed process typically requires at least forty-eight hours (and up to 144 hours) to substantially reduce the number of free radicals. While the process does reduce the number of free radicals contained within the UHMWPE, there can be significant costs associated with heating the irradiated formed implant of UHMWPE for such an extended period of time.
A need therefore exists for a process for effectively and rapidly quenching the free radicals present in irradiated UHMWPE. The invention provides such a process. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

Free radical quench process for irradiated ultrahigh molecular weight polyethylene


According to one embodiment, an image processing apparatus includes a buffer and processing circuitry. The buffer stores first and second images capturing an object. The circuitry calculates at least one of a first distance to the object in the first image and a second distance to the object in the second image by using a correction parameter for correcting at least one of influences caused by ambient light, a reflection characteristic of the object, or a color of the object, calculates three-dimensional coordinates of the object on a relative scale by using the first and second images, and calculates three-dimensional coordinates of the object on a real scale based on at least one of the first and second distances, and the three-dimensional coordinates of the object on the relative scale.

A technique for obtaining a distance to an object from images captured by two cameras or a stereo camera (binocular camera) is known. Furthermore, there is a technique recently proposed to obtain a distance to an object from images captured by one camera (monocular camera).
The captured images may be affected by ambient light or a reflection characteristic of the object. Obtaining the distance to the object with such images may decrease accuracy.

Image processing apparatus and ranging apparatus


A circuit and method of controlling the write and read operations of video data onto a line memory without occurrence of any data collision between odd fields occurs with the line memory providing a thermal print head of a video printer with printing data, in a frame-by-frame printing system. The line memory is provided with a frame-by-frame reading and writing system upon storing the video data therein and upon providing printing data to a thermal print head of the video printer. The video data of a first odd field corresponding to a first line during a first odd field period and the video data of a first even field corresponding to the first line during a first even field period are written into the line memory. The video data of a second odd field corresponding to a second line during a second odd field period and concurrently thereto, a read out is enabled for the first odd and even field video data corresponding to the first line from the line memory to therefrom print out the corresponding video data in the video printer. The consecutive reading, writing, and printing steps are repeated until completing all the scanning lines on a single video screen.

The present invention relates generally to controlling a memory in a video printer and in particular, to a method and circuitry for controlling the memory by adopting a frame line reading and writing system upon supplying printing data to a thermal print head of the video printer.
One of known arts for controlling a line memory providing a thermal print head (TPH) with printing data in a video printer is a field line system, a schematic block diagram of which system is disclosed in FIG. 2. Referring to this system, during a writing operation of printing data into a line memory 4, a controller 14 generates a given write address by controlling a write address counter 8, and a switch 10 transfers the write address from the write address counter to the line memory 14 under control of the controller 14. Hence, once analog video data from a video processor 1 are converted to digital data in an analog-to- digital converter 2 under control of the controller 14, the digital data are then supplied to the corresponding write address of the line memory 4 and stored therein as printing data for use in a subsequent printing operation of the video printer.
When reading the stored printing data out of the line memory 4 upon a printing operation, the switch 10 is connected to a read address counter 9, which under control of the controller 14 generates a set of read address to therefrom retrieve a corresponding one of the printing data previously stored in designated memory 4 allocations within the line memory, thereby transferring the read address to the line memory 4. Thus, a thermal print head (TPH) data processor 5 operably connected with the controller 14 and the line memory 4 receives the printing data read out of the line memory and, under control of the controller 14, provides the received data to a thermal print head (TPH) driver (not shown in the drawing) after processing a kind of conversion of printing data for better application in the TPH driver.
FIG. 1 illustrates the correlation between scanning of video data on a video screen and sampling of the video data to be stored into the line memory, by way of example, in view of the state of the art. Referring to this correlation, the video data on a single video screen are sampled and stored line by line into the line memory, and the stored video data are printed line by line, as follows: ##EQU1## wherein, n and m are respectively integer designations giving the maximum location of the video data scanning and sampling, and L.sub.1 through L.sub.m each designate a corresponding memory line in the line memory.
FIG. 3 is a schematic diagram for illustrating the correlation of consecutive read and write operations onto the line memory in the field line system, as shown in FIG. 2, provided with a repetition of one odd field and one even field of an input video signal. In this context of such a field line printing system every field of the input video signal is sequentially taken into the line memory by an interlacing scanning and sampling method. A common phenomenon of data collision occurs between odd fields such as a third field, a fifth field, a seventh field, etc., since the line memory is provided with only one input/output port in the usual cases. This data collision inevitably leads to poor picture quality in printing. Furthermore, while the line memory is usually adapted to store only video data corresponding to a single line to print out, it often fails to provide economical memory usage since nearly all commercially supplied memory devices do not fit such small sized line memory.
A U.S. Pat. No. 4,819,008 to Nagato et al. discloses a thermal print head driver circuit for a thermal printer permitting multiple graduation printing.

A frame line memory control circuit and method for controlling storage of video data of a video signal


A magnetoresistive sensor having a self biased free layer. The free layer is constructed upon an underlayer that has been treated by a surface texturing process that configures the underlayer with an anisotropic roughness that induces a magnetic anisotropy in the free layer. The treated layer underlying the free layer can be a spacer layer sandwiched between the free layer and pinned layer or can be a separate underlayer formed opposite the spacer layer. Alternatively, the texturing of an underlayer can be used to induce a magnetic anisotropy in a bias layer that is separated from the free layer by an orthogonal coupling layer. This self biasing of the free layer induced by texturing can also be used in conjunction with biasing from a hard-bias structure.

The heart of a computer's long term memory is an assembly that is referred to as a magnetic disk drive. The magnetic disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension arm adjacent to a surface of the rotating magnetic disk and an actuator that swings the suspension arm to place the read and write heads over selected circular tracks on the rotating disk. The read and write heads are directly located on a slider that has an air bearing surface (ABS). The suspension arm biases the slider toward the surface of the disk and when the disk rotates, air adjacent to the surface of the disk moves along with the disk. The slider flies on this moving air at a very low elevation (fly height) over the surface of the disk. This fly height is on the order of nanometers. When the slider rides on the air bearing, the write and read heads are employed for writing magnetic transitions to and reading magnetic transitions from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
In a typical design the write head includes a coil layer embedded in first, second and third insulation layers (insulation stack), the insulation stack being sandwiched between first and second pole piece layers. A gap is formed between the first and second pole piece layers by a gap layer at an air bearing surface (ABS) of the write head and the pole piece layers are connected at a back gap. Current conducted to the coil layer induces a magnetic flux in the pole pieces which causes a magnetic field to fringe out at a write gap at the ABS for the purpose of writing the aforementioned magnetic impressions in tracks on the moving media, such as in circular tracks on the aforementioned rotating disk.
In recent read head designs a spin valve sensor, also referred to as a giant magnetoresistive (GMR) sensor, has been employed for sensing magnetic fields from the rotating magnetic disk. This sensor includes a nonmagnetic conductive layer, hereinafter referred to as a spacer layer, sandwiched between first and second ferromagnetic layers, hereinafter referred to as a pinned layer and a free layer, both of which can be made up by a plurality of layers. First and second leads are connected to the spin valve sensor for conducting a sense current therethrough. The magnetization of the pinned layer is pinned substantially perpendicular to the air bearing surface (ABS) and is relatively insensitive to applied magnetic fields. The magnetic moment of the free layer is biased parallel to the ABS, but is free to rotate in response to external magnetic fields. The magnetization of the pinned layer is typically pinned by exchange coupling with an antiferromagnetic layer.
The thickness of the spacer layer is chosen to be less than the mean free path of conduction electrons through the sensor. With this arrangement, a portion of the conduction electrons is scattered by the interfaces of the spacer layer with each of the pinned and free layers. When the magnetizations of the pinned and free layers are parallel with respect to one another, scattering is minimal and when the magnetizations of the pinned and free layer are antiparallel, scattering is maximized. Changes in scattering alter the resistance of the spin valve sensor in proportion to cos θ, where θ is the angle between the magnetizations of the pinned and free layers. Since θ is near 90 degrees at zero field, the resistance of the spin valve sensor (for small rotations of the free layer from 90 degrees) changes proportionally to the magnitudes of the magnetic fields from the rotating disk. When a sense current is conducted through the spin valve sensor, resistance changes cause potential changes that are detected and processed as playback signals.
When a spin valve sensor employs a single pinned layer it is referred to as a simple spin valve. When a spin valve employs an antiparallel (AP) pinned layer it is referred to as an AP pinned spin valve. An AP pinned spin valve includes first and second magnetic layers separated by a thin non-magnetic coupling layer such as Ru or Ir. The thickness of the coupling layer is chosen so as to antiparallel couple the magnetic moments of the ferromagnetic layers of the pinned layer. A spin valve is also known as a top or bottom spin valve depending upon whether the pinning layer is at the top (formed after the free layer) or at the bottom (before the free layer).
Magnetization of the pinned layer is usually fixed by exchange coupling one of the ferromagnetic layers (AP1) with a layer of antiferromagnetic material such as PtMn. While an antiferromagnetic (AFM) material such as PtMn does not in and of itself have a net magnetic moment, when exchange coupled with a magnetic material, it can strongly pin the magnetization of the ferromagnetic layer.
A current in plane (CIP) spin valve sensor is located between first and second nonmagnetic electrically insulating read gap layers and the first and second read gap layers are located between ferromagnetic first and second shield layers. In a merged magnetic head a single ferromagnetic layer functions as the second shield layer of the read head and as the first pole piece layer of the write head. In a piggyback head the second shield layer and the first pole piece layer are separate layers.
The ever increasing demand for greater data rate and recording density has lead a push to develop current perpendicular to the plane (CPP) sensors which are uniquely suited to use in such systems. CPP sensors include both CPP giant magneto-resistive (GMR) sensors, which use an electrically conductive spacer layer such as Cu as well as tunnel magneto-resistive (TMR) sensors, which use a thin, electrically insulating barrier layer like Al-oxide. The CPP GMR sensor operates based on spin-dependent bulk and interface scattering of the electrons while the TMR sensor operates based on the spin dependent tunneling of electrons through the barrier layer.
In order to stabilize the free layer in CIP GMR, CPP GMR, or CPP TMR sensors against fluctuations due to thermal agitation and to prevent it from breaking up into domains it needs to be biased. One form of biasing a sensor is by using a hard magnetic biasing layer, typically a Col-xPtx or Col-x-yPtxCry alloy (x being between 10 and 35 atomic % and y between 0 and 15 atomic %) deposited onto a suitable underlayer material on both sides and about the same level as the free layer. Typically the hard magnetic bias layers also comprise a seed layer of Cr or CrX (X═Mo,Ti,V) on which the magnetic Col-xPtx or Col-x-yPtxCry material is deposited to achieve crystalline texture and sufficiently high coercivity. An insulating gap separates the free and the hard biasing layers in CPP sensors to prevent electrical shunting. The hard magnetic bias layer has sufficiently high coercivity and remanence so that its remanent moment magnetostatically biases the free layer in a direction substantially parallel to the ABS. The total moment of the hard bias layer is typically several times the magnetic moment of the free layer. The actual moment value depends on the hard bias material, its shape and separation from the free layer.
Another approach to biasing the free layer is in-stack biasing where an in-stack bias layer is separated from the free layer by a non-magnetic spacer layer. The free layer is stabilized magnetostatically by flux closure and is generally antiparallel to the biasing layer. The biasing layer is typically exchange biased to an antiferronmagnet to pin its moment in a desired direction parallel to the medium facing surface. Alternatively, the bias layer moment can be pinned by using a hard magnet. Yet another approach to biasing the free layer is to insert an orthogonal coupling layer between the free layer and the bias layer. The orthogonal coupling layer is a material that magnetically couples the free and the bias layer in substantially orthogonal directions. The biasing layer is typically exchange biased to an antiferronmagnet to pin its moment in a desired direction perpendicular to the medium facing surface.
One major problem with stabilizing the free layer by external sources such as hard-biasing, in-stack biasing, or biasing with a orthogonal coupling layer is that they increase the complexity of the device. Hard biasing and in-stack biasing rely on magnetostatic coupling with the free layer, which is difficult to control for small sensor sizes. In-stack biasing and biasing with an orthogonal coupling layer increase the sensor stack-height which make these approaches less suitable as gap sizes are reduced for higher recording densities.
Therefore, there is a strong felt need for a mechanism to generate a uniaxial magnetic anisotropy in the free layer which may either be sufficient to self bias the free layer in a direction substantially parallel to the medium facing surface of the sensor or to augment biasing from external sources such as hard biasing or in-stack biasing. As used herein substantially parallel means that the easy axis is closer to parallel than perpendicular to the ABS.

Magnetic read sensor employing oblique etched underlayers for inducing uniaxial magnetic anisotropy in a self biased free layer

Hitachi Global Storage Technologies Netherlands B.V.


Methods and systems are provided for an evaporative emissions control system for onboard refueling vapor recovery of a heavy duty vehicle. In one example, a method may include, in response to greater than a threshold change in a fuel level of a fuel tank fluidically coupled to at least two fuel vapor storage canisters of an evaporative emissions control system during a refueling event, performing a canister working capacity diagnostic on each of the at least two fuel vapor storage canisters by measuring an exhaust gas air-fuel ratio (AFR) while independently purging each of the at least two fuel vapor storage canisters. In this way, the working capacity of each fuel vapor storage canister may be separately assessed in order to more accurate identify degradation of the working capacity.

Vehicle emission control systems may be configured to store fuel vapors from fuel tank refueling, diurnal emissions, and running loss vapors and then purge the stored vapors during a subsequent engine operation. Specifically, the fuel vapors (e.g., vaporized hydrocarbons) are stored in a fuel vapor storage canister, also referred to herein as a "canister," that is packed with an adsorbent (e.g., activated carbon) that adsorbs and stores the vapors until they are routed to an engine intake manifold for use as fuel. In a hybrid vehicle, the fuel vapors stored in the canister are primarily refueling vapors.
Two different types of systems are typically used for recovery of refueling vapors: onboard refueling vapor recovery (ORVR) system and off-board refueling vapor recovery (e.g., non-ORVR) systems. Examples of conventional vehicles using non-ORVR systems may include heavy duty vehicles weighing over 8500 pounds. In a vehicle using a non-ORVR system, refueling vapors may be recovered by gas station infrastructure, such as an underground recovery tank. The gas station infrastructure may include refueling nozzles with boots that seal around a filler neck for off-board recovery. However, some gas station infrastructures may not include refueling nozzles configured for off-board recovery, and so fuel vapors may escape to atmosphere.
As such, it may be desirable to transition heavy duty vehicles to using ORVR systems in order to reduce refueling emissions. Typically, a size of a fuel vapor storage canister is proportional to a size of a fuel tank. However, incorporating a large canister in vehicles including large (e.g., 80 gallon) fuel tanks may pose challenges during vehicle refueling. For example, large canisters may restrict vapor flow in the canister, producing system back pressure from the canister as fuel vapors from refueling are loaded into the canister. A back pressure of 10 inH2O may shut off a refueling pump, resulting in slow or incomplete refueling. Therefore, multiple smaller canisters may be arranged in parallel to provide a refueling vapor capacity for large fuel tanks while reducing canister restriction.
However, canisters age over time and/or may become contaminated (e.g., via water ingestion, liquid fuel carryover, or carbon pellet breakdown). As a result, the adsorbent may become degraded and no longer adsorb or desorb fuel vapor. Without a method to individually test a working capacity of each canister, it may be difficult to identify when one canister in a parallel configuration is not adsorbing and desorbing fuel vapors as intended. Further, operating with a degraded canister may increase evaporative emissions.
In one example, the issues described above may be addressed by a method, comprising, in response to greater than a threshold change in a fuel level of a fuel tank fluidically coupled to at least two fuel vapor storage canisters of an evaporative emissions control system during a refueling event, performing a canister working capacity diagnostic on each of the at least two fuel vapor storage canisters by measuring an exhaust gas air-fuel ratio (AFR) while independently purging each of the at least two fuel vapor storage canisters. In this way, the working capacity of each fuel vapor storage canister may be separately assessed in order to more accurate identify degradation of the working capacity of individual canisters.
As one example, one of the at least two fuel vapor storage canisters may be selected to be assessed via the canister working capacity diagnostic at a time. The selected fuel vapor storage canister may be independently purged by opening or maintaining open a first canister vent valve (CVV) coupled between a first vent port of the selected fuel vapor storage canisters and a vent line, closing or maintaining closed a CVV coupled between a vent port of each of the at least two fuel vapor storage canisters that is not the selected fuel vapor storage canister and the vent line. For example, closing or maintaining closed the CVV coupled between the vent port of each of the at least two fuel vapor storage canisters that is not the selected fuel vapor storage canister may prevent vapor flow across each of the at least two fuel vapor storage canisters that is not the selected fuel vapor storage canister. Further, a balance valve that is coupled between the fuel tank and a branched loading passage coupling the fuel tank to each of the at least two fuel vapor storage canisters may be adjusted to a first position where the fuel tank is fluidically coupled to the selected fuel vapor storage canister and not fluidically coupled to each of the at least two fuel vapor storage canisters that is not the selected fuel vapor storage canister. The independent purging of the selected fuel vapor storage canister may be initiated by opening a canister purge valve (CPV) positioned in a branched purge passage that fluidically couples an engine intake to a purge port of each of the at least two fuel vapor storage canisters.
As another example, degradation of the working capacity of the selected fuel vapor storage canister may be indicated in response to the exhaust gas AFR shifting lean upon opening the CPV, whereas the working capacity may be determined in proportion to a magnitude of the exhaust gas AFR in response to the exhaust gas AFR shifting rich upon opening the CPV. Further, the selected fuel vapor storage canister may be sealed to prevent vapor flow across the selected fuel vapor storage canister in response to the degradation of the working capacity being indicated. For example, the first CVV may be maintained closed, and the balance valve may not be adjusted to a position that fluidically couples the selected fuel vapor storage canister to the fuel tank. Further still, a refueling capacity of the fuel tank may be reduced for subsequent refueling events in response to the degradation of the working capacity being indicated.
In this way, the working capacity of each of a plurality of parallel fuel vapor storage canisters may be separately diagnosed by separately purging a canister following a refueling event that is expected to fully load each canister. As a result, exhaust gas AFR measurements may indicate the working capacity of only the fuel vapor storage canister being purged, and so fuel vapors stored in other fuel vapor storage canisters may not confound the measurements. By accurately identifying a degraded fuel vapor storage canister and preventing the degraded fuel vapor storage canister from being used, vehicle evaporate emissions may be decreased.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Canister capacity diagnostics for evaporative emissions control system in heavy duty vehicles


A sheet feeding apparatus is provided that includes a sheet feeding tray 21 that can rotate to open and close; a sheet positioning portion 25a disposed in a sheet feeding portion such that it can contact against a side end of stacked sheets S; an edge limiting member 211 disposed in the sheet feeding tray such that it can contact against a side end of the sheets on a side that is further upstream than the sheet positioning portion; and a control unit that controls an inverted posture of the edge limiting member in response to an operation to open or close the sheet feeding tray; wherein the edge limiting member rises accompanying an operation to open the sheet feeding tray and the edge limiting member collapses accompanying an operation to close the sheet feeding tray.

1. Field of the Invention
The present invention relates to a sheet feeding apparatus equipped with a sheet feeding tray that can rotate to open or close, and a recording apparatus and an image reading apparatus equipped with the sheet feeding apparatus.
2. Description of the Related Art
In a recording apparatus that records an image on a recording medium or an image reading apparatus that scans an image from an original, a sheet feeding apparatus is used to feed a recording medium in sheet form or a sheet as an original to an image forming portion or reading portion of the like. Examples of a recording apparatus include a printer, a copier, a facsimile, and a multifunction device or system using these. Examples of an image reading apparatus include a scanner and a multifunction device or system using the scanner. In the present application, the term "image" is used in a broad sense to include characters, symbols, line drawings, patterns and the like.
A sheet feeding apparatus comprises a sheet feeding tray for stacking sheets. As described in Japanese Patent Application Laid-Open No. H11-301045, a sheet feeding apparatus is known in which a sheet feeding tray is mounted in a condition whereby it can open and close in a rotatable manner. FIG. 12 is an oblique perspective view of a recording apparatus equipped with the conventional sheet feeding apparatus that shows the sheet feeding tray in an open state. FIG. 13 is an oblique perspective view of the recording apparatus of FIG. 12 that shows the sheet feeding tray in a closed state. According to the sheet feeding apparatus having the sheet feeding tray that can rotate to open or close as shown in FIG. 12 and FIG. 13, closing a sheet feeding tray 101 to store it inside the apparatus enables space saving and enhancement of aesthetic characteristics, and reliability can also be improved as the inside of the apparatus is protected from dust and the like. Further, according to this sheet feeding apparatus, a side guide is provided in the main body and the sheet feeding tray 101, respectively, for regulating the position and inclination of sheets by contacting against the side edge of stacked sheets.
More specifically, on the main body side a side guide 102 is provided as a positioning member that positions sheets, in the width direction (direction parallel to the feeding plane and perpendicular to the feeding direction) by contacting against the side edge in the vicinity of the leading end of sheets that are stacked in the sheet feeding tray. At the top part of the sheet feeding tray 101 that is capable of rotating to open or close is provided a side guide 101a as an inclination limiting member that limits an inclination within the feeding plane of sheets by contacting against the side edge of stacked sheets at a position further upstream than the side guide on the main body side. When the sheet feeding tray is in a folded-up state, the side guide 101a is contained in a recess portion formed in the upper case of the sheet feeding apparatus. According to this sheet feeding apparatus, the skewing of sheets can be reduced while still allowing the sheet feeding tray to open and close in a rotatable manner.
However, in the above described conventional example, it is only possible to provide the inclination limiting member 101a in a limited area at the top part of the sheet feeding tray due to space concerns or the configurational relationship with other constituent members when the sheet feeding tray 101 is folded up. Thus, an inclination limiting effect can not be expected after the rear end of a sheet passes the inclination limiting member. Further, an inclination limiting effect can also not be expected in the case of a sheet whose rear edge does not reach the inclination limiting member because the dimensions of the sheet in the length direction are short. Consequently, the conventional technology attempts to equalize a resistance force or a sheet feeding force that act on a sheet while it is being fed by disposing a plurality of sheet feeding means and a plurality of separation means in the sheet width direction in a well balanced manner and making it possible for them to move in the sheet width direction, to thereby reduce skew feeding of sheets. In this case, the inclination limiting member 101a is used in an auxiliary manner.
Further, in a sheet feeding apparatus in which priority is given to simplification of the apparatus or weight reduction, simplification and weight reduction with respect to sheet feeding means or separation means has been attempted by imparting the principal feeding force to a sheet at a fixed position at one location that is nearer the positioning member than the center of the width direction of the sheet. According to this configuration, skewing of a sheet is liable to occur since the balance of the feeding force or resistance force in the width direction of a sheet is poor. In order to avoid this kind of problem, a large inclination limiting member is provided in the sheet feeding tray and a positioning member provided on the main body side is made larger to simultaneously exert an inclination limiting effect.
However, in a common sheet feeding apparatus, since a sheet bundle comprising a plurality of sheets is stacked in the sheet feeding tray and only the uppermost sheet thereof is separated and fed, it is necessary for the height of the above described positioning member or inclination limiting member to be at least greater than or equal to the thickness (stack height) of the bundle of sheets. Consequently, disadvantages have arisen such as it being spatially impossible to store or fold up the sheet feeding tray, or the number of sheets that can be stacked in the sheet feeding tray being reduced. Other disadvantages include the fact that the size of the sheet feeding apparatus becomes large when the sheet feeding tray is folded up and stored, and the size of the main body side of the sheet feeding apparatus increases. Furthermore, since a sheet feeding tray comprising the inclination limiting member is supported by an external cover, a position of the inclination limiting member with respect to the positioning member is positioned via a sheet feeding frame, the external cover and the sheet feeding tray. Therefore, the position deviation precision in the width direction of the sheet is low, and skewing of the sheet can not be adequately suppressed.

Sheet feeding apparatus, and recording apparatus and reading apparatus comprising same


A display system in which the luminance of light-emitting elements in a light-emitting device is adjusted based on information on an environment. A sensor obtains information on an environment as an electrical signal. A CPU converts, based on comparison data set in advance, the information signal into a correction signal for correcting the luminance of EL elements. Upon receiving this correction signal, a voltage changer applies a predetermined corrected potential to the EL elements. Thus, this display system enables control of the luminance of the EL elements.

1. Field of the Invention
The present invention relates to a display system and an electrical appliance capable of brightness control based on information on surroundings.
2. Description of the Related Art
In recent years, the development of display devices using electro luminescent (EL) elements (hereinafter referred to as EL display device) has been advanced. EL elements are of self-light-emitting type devised by utilizing the phenomena of electro luminescence (including fluorescence and phosphorescence) from organic EL materials. Since EL display devices are of a self-light-emitting type, they require no backlight such as that for liquid crystal display devices and have a large viewing angle. For this reason, EL display devices are regarded as a promising display portion for use in portable devices used outdoors.
There are two types of EL display devices: a passive type (simple matrix type) and an active type (active matrix type). The development of either type of EL display devices is being promoted. In particular, active matrix EL display devices are presently receiving attention. Organic materials for forming light-emitting layers of EL elements are grouped into low-molecular (monomeric) organic EL materials and high-molecular (polymeric) organic EL materials. Studies of these kinds of materials are being actively made.
None of EL display devices and light-emitting devices including semiconductor diodes, heretofore known, has any function of controlling the luminance of a light-emitting element in the light-emitting device based on information on surroundings of the light-emitting device.

Semiconductor Energy Laboratory Co., Ltd.


A signaling method for a terminal that performs direct communication between terminals terminal is disclosed. A transmitting terminal transmits a link establishment request message for establishing a link to a receiving terminal, and the receiving terminal transmits a link establishment response message responding to this message to the transmitting terminal. The link establishment request message includes a field indicating a flow to use if the receiving terminal acquires a token.

(a) Field of the Invention
The present invention relates to a signaling method for direct communication between terminals.
(b) Description of the Related Art
Direct communication refers to signal transmission and reception between terminals without mediation with a base station or control therebetween. As demand for direct communication between terminals is on the rise, a direct communication method within or outside an infrastructure communication region is required.
Standards for direct communication between terminals include IEEE Std. 802.16.1a. The IEEE Std. 802.16.1a is a standard that allows for direct communication between terminals as resources dedicated for direct communication are allocated in time and frequency domains in a frame structure of infrastructure communication between a base station and a terminal, and signals are exchanged between terminals through allocated radio resources.
To provide different QoS for each traffic stream in a radio resource region, flows are established at a MAC layer, and a MAC PDU (packet data unit) is constructed for each flow. In talk-around direct communication (TDC) according to IEEE Std. 802.16.1a, flow IDs (FIDs) are established in a unidirectional link establishment process, and the transmitting side configures the FIDs to not overlap. However, if the direction of unidirectional traffic is changed by a token handover procedure, the traffic source may be changed to a terminal with no FID. In this case, the transmitting terminal is not able to construct a MAC PDU for the terminal with no FID.
A multicast connection involves transmitting data to a plurality of user groups. A connection setup procedure is performed in the step of setting up an initial multicast connection, by which a multicast connection group is created. However, the existing IEEE Std. 802.16.1a does not provide for an operation scenario for a user (terminal) who leaves the multicast connection group. Also, this standard does not define a procedure of transmitting multicast connection setup information after the setup step, and therefore additional users who want to participate in the multicast connection group may not be able to participate in the multicast connection group.
The IEEE Std. 802.16.1a does not define a procedure of detecting the presence or absence of a receiving terminal within a communication distance when making a unidirectional unicast and multicast connection, or releasing a connection that fails to connect to a communication channel.

Signalling method for direct communication between terminals

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE


A lubricating nutating single cone drill bit 10 is disclosed. Bit 10 includes a bit shank 12 with an axially skewed bore 18 rotatably retaining a cutter body 22. A plurality of cutter elements (46, 48) are affixed to the cutter body 22. Bearings (26, 28, 30, 32) enable rotation of the cutter body 22 and lubricant is dispensed to the bearings from a lubricant chamber (76, 76′) by a plunger 80 driven by drilling fluid. A method to drill includes attaching the bit 10 to a drill string, engaging the bit 10 into a formation (WB), pumping a drilling fluid into a plunger 80 in the lubricant chamber 76 to dispense lubricant to the bearings (26, 28, 30, 32). The method can include pumping the drilling fluid through a fluid passage 90 in the bit 10 and out of a low pressure orifice 94 on the cutter body 22.

The present invention generally relates to drill bits for boring subterranean and sub sea formations. More particularly, the present invention relates to a lubricating nutating single cone drill bit having an axis of rotation skewed relative to the central axis of the bit body in the borehole providing low torque and allowing high compressive loading on the bit assembly.
A number of single cone drill bits have been proposed through the years to drill bore holes for mining, oil and gas exploration, and utility construction. It has been previously recognized that a single cone bit would offer superior design characteristics, such as bearing size permitting greater longitudinal compressive loading on the drill bit. Previous single cone drill bits however provided substantial scraping of the cutter elements causing abnormal wear and torque on the drill string assembly.
Each of the prior single cone drill bits were subject to excessive wearing of the cutting elements because at least during some portion of the rotation, the cutter elements were dragged by the circular motion of the bit on the journal across the formation face rather than moved in compressive engagement with the surface. These cutter elements are designed to have long use lives if used in compression, but have a tendency to break if subjected to side shear or scraping. A nutating single cone drill bit, for example the one disclosed in U.S. Pat. No. 6,892,828, incorporated by reference herein, can offer the advantage of long wearing cutter elements. Typically, traditional tri-cone bits must be repeatedly tripped out of the borehole due to excessively worn cutter elements. Since a nutating single cone drill bit allows for longer service life, the extended periods of down-hole use can be limited by the amount of available lubrication sufficient to maintain the bearings of the nutating single cone bit. Without sufficient lubrication, the bearing can fail prior to the cutter elements of the bit wearing, limiting the usefulness of the nutating single cone drill bit.

Drill bit lubrication apparatus and method


The invention is directed to a method of synthesizing a molecular sieve. In particular, the invention is directed to a method for synthesizing a molecular sieve, especially a silicoaluminophosphate molecular sieve, in the presence of a templating agent and a polymeric base. The invention is also directed to formulating the molecular sieve into a catalyst useful in a process for producing olefin(s), preferably ethylene and/or propylene, from a feedstock, preferably an oxygenate containing feedstock.

Olefins are traditionally produced from petroleum feedstock by catalytic or steam cracking processes. These cracking processes, especially steam cracking, produce light olefin(s) such as ethylene and/or propylene from a variety of hydrocarbon feedstock. Ethylene and propylene are important commodity petrochemicals useful in a variety of processes for making plastics and other chemical compounds. Ethylene is used to make various polyethylene plastics, and in making other chemicals such as vinyl chloride, ethylene oxide, ethylbenzene and alcohol. Propylene is used to make various polypropylene plastics, and in making other chemicals such as acrylonitrile and propylene oxide.
The petrochemical industry has known for some time that oxygenates, especially alcohols, are convertible into light olefin(s). There are numerous technologies available for producing oxygenates including fermentation or reaction of synthesis gas derived from natural gas, petroleum liquids, carbonaceous materials including coal, recycled plastics, municipal waste or any other organic material. Generally, the production of synthesis gas involves a combustion reaction of natural gas, mostly methane, and an oxygen source into hydrogen, carbon monoxide and/or carbon dioxide. Syngas production processes are well known, and include conventional steam reforming, autothermal reforming, or a combination thereof.
Methanol, the preferred alcohol for light olefin production, is typically synthesized from the catalytic reaction of hydrogen, carbon monoxide and/or carbon dioxide in a methanol reactor in the presence of a heterogeneous catalyst. For example, in one synthesis process methanol is produced using a copper/zinc oxide catalyst in a water-cooled tubular methanol reactor. The preferred methanol conversion process is generally referred to as a methanol-to-olefin(s) process, where methanol is converted to primarily ethylene and/or propylene in the presence of a molecular sieve.
Molecular sieves are porous solids having pores of different sizes such as zeolites or zeolite-type molecular sieves, carbons and oxides. There are amorphous and crystalline molecular sieves. Molecular sieves include natural, mineral molecular sieves, or chemically formed, synthetic molecular sieves that are typically crystalline materials containing silica, and optionally alumina. The most commercially useful molecular sieves for the petroleum and petrochemical industries are known as zeolites. A zeolite is an aluminosilicate having an open framework structure that usually carries negative charges. This negative charge within portions of the framework is a result of an Al3+ replacing a Si4+. Cations counter-balance these negative charges preserving the electroneutrality of the framework, and these cations are exchangeable with other cations and/or protons. Synthetic molecular sieves, particularly zeolites, are typically synthesized by mixing sources of alumina and silica in a strongly basic aqueous media, often in the presence of a structure directing agent or templating agent. The structure of the molecular sieve formed is determined in part by solubility of the various sources, silica-to-alumina ratio, nature of the cation, synthesis temperature, order of addition, type of templating agent, and the like.
A zeolite is typically formed from corner sharing the oxygen atoms of [SiO4] and [AlO4] tetrahedra or octahedra. Zeolites in general have a one-, two- or three-dimensional crystalline pore structure having uniformly sized pores of molecular dimensions that selectively adsorb molecules that can enter the pores, and exclude those molecules that are too large. The pore size, pore shape, interstitial spacing or channels, composition, crystal morphology and structure are a few characteristics of molecular sieves that determine their use in various hydrocarbon adsorption and conversion processes.
There are many different types of zeolites well known to convert a feedstock, especially oxygenate containing feedstock, into one or more olefin(s). For example, U.S. Pat. No. 5,367,100 describes the use of a well known zeolite, ZSM-5, to convert methanol into olefin(s); U.S. Pat. No. 4,062,905 discusses the conversion of methanol and other oxygenates to ethylene and propylene using crystalline aluminosilicate zeolites, for example Zeolite T, ZK5, erionite and chabazite; and U.S. Pat. No. 4,079,095 describes the use of ZSM-34 to convert methanol to hydrocarbon products such as ethylene and propylene.
Crystalline aluminophosphates, ALPO4, formed from corner sharing [AlO2] and [PO2] tetrahedra linked by shared oxygen atoms are described in U.S. Pat. No. 4,310,440 to produce light olefin(s) from an alcohol. Metal containing aluminophosphate molecular sieves, MeAPO's and ElAPO's, have been also described to convert alcohols into olefin(s). MeAPO's have a [MeO2], [AlO2] and [PO2] tetrahedra microporous structure, where Me is a metal source having one or more of the divalent elements Co, Fe, Mg, Mn and Zn, and trivalent Fe from the Periodic Table of Elements. ElAPO's have an [ElO2], [AlO2] and [PO2] tetrahedra microporous structure, where El is a metal source having one or more of the elements As, B, Be, Ga, Ge, Li, Ti and Zr. MeAPO's and ElAPO's are typically synthesized by the hydrothermal crystallization of a reaction mixture of a metal source, an aluminum source, a phosphorous source and a templating agent. The preparation of MeAPO's and ElAPO's are found in U.S. Pat. Nos. 4,310,440, 4,500,651, 4,554,143, 4,567,029, 4,752,651, 4,853,197, 4,873,390 and 5,191,141.
One of the most useful molecular sieves for converting methanol to olefin(s) are those ELAPO's or MeAPO's where the metal source is silicon, often a fumed, colloidal or precipitated silica. These molecular sieves are known as silicoaluminophosphate molecular sieves. Silicoaluminophosphate (SAPO) molecular sieves contain a three-dimensional microporous crystalline framework structure of [SiO2], [AlO2] and [PO2] corner sharing tetrahedral units. SAPO synthesis is described in U.S. Pat. No. 4,440,871, which is herein fully incorporated by reference. SAPO is generally synthesized by the hydrothermal crystallization of a reaction mixture of silicon-, aluminum- and phosphorus-sources and at least one templating agent. Synthesis of a SAPO molecular sieve, its formulation into a SAPO catalyst, and its use in converting a hydrocarbon feedstock into olefin(s), particularly where the feedstock is methanol, is shown in U.S. Pat. Nos. 4,499,327, 4,677,242, 4,677,243, 4,873,390, 5,095,163, 5,714,662 and 6,166,282, all of which are herein fully incorporated by reference.
Templating agents are used in the synthesis of molecular sieves, particularly SAPO molecular sieves, as a crystal structure-directing agent or affecting agent. Furthermore, templating agents are typically nitrogen containing organic bases such as quaternary ammonium salts or hydroxides. Typically, because templating agents are also used to control the pH during the synthesis of molecular sieves, the quaternary ammonium hydroxide is often used instead of the less expensive quaternary ammonium salt. Additionally, the quantity of the templating agent used is often dictated by the pH of the reaction mixture in which the molecular sieve forms. Templating agents are typically used in excess, relative to its incorporation in the crystalline molecular sieve product, in order to control the pH and/or alkaline content in the synthesis of molecular sieves, for example as described in U.S. Pat. No. 4,440,871.
The templating agent is oftentimes the most costly ingredient used in synthesizing molecular sieves. Using a second, less expensive base as a pH controller, in addition to a templating agent, in principle leads to a reduction in the cost of synthesizing a particular molecular sieve, provided that the pH controller does not interfere with the synthesis of the desired molecular sieve. As described in U.S. Pat. No. 4,440,871 in a SAPO molecular sieve synthesis, using an inorganic base to reduce the amount of organic templating agent, often results in the formation of undesirable dense phase products. Some organic bases, for instance, dipropylamine, have been combined with a templating agent, tetraethylammonium hydroxide, for the synthesis of a SAPO molecular sieve. Monomeric organic bases such as dipropylamine are volatile and raise various environmental and safety concerns. Additionally, higher pressure equipment is needed for the hydrothermal synthesis of molecular sieves using volatile monomeric organic bases.
Therefore, it would be desirable to have an improved method for reducing the amount of templating agent utilized in synthesizing a molecular sieve.


A wireless communication system controls a transmission timing in each cell so that a control channel of a first cell and a data channel of a second cell temporally overlap each other. The wireless communication system includes a base station of the first cell. The base station of the first cell includes a first control unit and a first communicating unit. The first control unit notifies a base station of the second cell of information used to specify a resource of the control channel of the first cell. The first communicating unit transmits a control signal to a mobile station of the first cell by using a first resource of the control channel of the first cell.

Conventionally, for LTE (Long Term Evolution) or LTE-Advanced as a next generation mobile communication system, a heterogeneous network has been studied in order to improve system capacity and coverage. The heterogeneous network is a network in which a macrocell and a cell of a base station with low transmission power (hereinafter, described as a "picocell") are arranged so as to coexist with each other. In such a network, when the macrocell and the picocell are operated at the same frequency, interference from the macrocell to the picocell becomes a problem. Namely, in a mobile station connected to a base station of the picocell (hereinafter, described as a "pico base station"), a signal from the pico base station is interfered with by a signal from a base station of the macrocell (hereinafter, described as a "macro base station").
The inter-cell interference as described above influences the communication quality in each of physical channels (a control channel and a data channel). In particular, in a system in which a transmission timing of a subframe is synchronized between cells, the inter-cell interference may occur between the control channels and between the data channels. As a technology for reducing the inter-cell interference as described above, there is a technology for shifting a transmission timing of a subframe in the pico base station with respect to a transmission timing of a subframe in the macro base station, in an OFDM (Orthogonal Frequency Division Multiplexing) symbol unit. In such a technology, a data channel of the macro base station that overlaps a control channel of the pico base station in the time domain as a result of the shift is overwritten (muting) with a null symbol with transmission power of zero.    Non Patent Literature 1: 3GPP TR 36.814 V9.0.0 (2010-03)    Non Patent Literature 2: 3GPP TS 36.211 V8.9.0 (2009-12)    Non Patent Literature 3: 3GPP TS 36.213 V8.8.0 (2009-09)    Non Patent Literature 4: 3GPP R1-103227
However, in the technology described above, while interference from the data channel of the macro base station to the control channel of the pico base station is reduced, there is a problem in that the reception characteristics of the data channel of the macro base station is degraded. Namely, because a null symbol is set in a resource that is muted to reduce the interference among resources of the data channel of the macro base station, the amount of data that the macro base station can transmit per unit time is reduced accordingly. The reduction in the amount of transmission data is a cause of degradation of the reception characteristics of the data channel.

Wireless communication system, base station, mobile station, and wireless communication method


A magnetic data storage system includes at least one storage disk having a data surface of concentric radial tracks and at least one burnishing track, a drive for rotating the disk; and a slider having an air bearing surface for air support of the slider over the data surface, wherein the burnishing track is a dedicated track for burnishing the slider.

1. Field of the Invention
The present invention generally relates to magnetic data storage systems and to sliders used in such systems. More particularly, the invention concerns a method and apparatus for burnishing sliders during, as well as after manufacture and assembly of the system.
2. Discussion of the Related Art
A magnetic data storage system typically comprises at least one magnetic disk with at least one data recording surface having a plurality of concentric tracks for storing data. A spindle motor and spindle motor controller rotate the disk(s) at selected revolutions per minute (RPM) such that at least one read/write transducer can read data from or write data to a recording surface. In most current systems, the transducer is supported by an air bearing slider which has a top surface attached to an actuator assembly via a suspension, and a bottom surface having an air bearing design and pads to provide favorable flying height of the slider. During operation of the magnetic data storage system, the air bearing slider is positioned above the desired data track by an actuator assembly.
Recently, the recording density of magnetic disks has dramatically increased. In order to take advantage of the increased density, the flying height of the magnetic head has been reduced to 0.1 xcexcm or less. In fact, systems using continuous contact sliders, in which the sliders stay in touch with the disk during all aspects of operation, have been proposed. In such contact recording systems, the magnetic heads read and write in contact with the magnetic disk. U.S. Pat. No. 5,041,932 and Japanese Patent Application Laid-open No. H5-114116 disclose magnetic head structures suitable for such contact recording and reproducing, and a method of manufacturing such structures.
However, inherent in the contact recording and reproducing system is the abrasion of the magnetic head and the magnetic disk due to the sliding contact between them. This problem may be reduced by using a carbon material in the contact pad portion of the head, a protective layer on the magnetic disk, a reduced weight magnetic head, a reduced load head, and/or a perpendicular magnetic recording system. Nonetheless, wear, uneven surfaces, and debris intrinsic in these contact slider systems shortens their life.
For this reason, some of the more conventional magnetic storage systems use air bearing sliders that operate in a contact start/stop mode. The slider and transducer are only in contact with the recording surface when the spindle motor is powered down. As the disk begins to rotate, an air flow is generated which enters the leading edge of the slider and flows in the direction of the trailing edge of the slider. The air flow generates a positive pressure on the air bearing surface of the slider, and when enough pressure builds up, lifts the slider above the recording surface. As the spindle motor reaches the operating RPM, the slider is maintained at a nominal flying height over the recording surface by a cushion of air. Subsequently, as the spindle motor spins down, the flying height of the slider drops until the slider is once again in contact with the disk.
However, due to the slider dragging on the disk surface during start and stop operations, these air-bearing systems, the resulting wear (also referred to as wear durability), unevenness, and debris on the disk and slider surfaces severely reduces system life. Moreover, the entire system may xe2x80x9ccrashxe2x80x9d (ie. the system becomes nonfunctional due to damage) if such contact causes damage to a critical part of the disk or slider, or creates debris that becomes caught between the slider and disk or other crucial components. Additionally, protrusions or uneven slider surfaces created by contact may cause read/write errors, further disk wear, and crashes. Similarly, slider/disk contact may cause improper slider flying height due to inadvertent burnishing, buildup of debris on the slider, or changes in the flight characteristics of the slider.
The flying height of the slider transducer head above the disk is critical for mechanical and magnetic performance. Transducer heads flying too high perform poorly magnetically, for example, providing a readback signal with reduced amplitude, a reduced signal to noise ratio and a reduced resolution for bit detection. On the other hand, transducer heads flying too low are more likely to pick up contamination from the disk that will lead to smears on the heads and to an increase of the hazard of head crashes. One approach to circumvent the undesirable issues associated with wear, durability, and improper flying height is to use load/unload technology.
Typical load/unload technology includes a ramp for the slider/suspension assembly at the outer diameter of the disk where the slider is xe2x80x9cparkedxe2x80x9d securely while the spindle motor is powered down. During normal operation, the disk speed is allowed to reach a selected RPM (which may be below the normal operating RPM) before the head is xe2x80x9cloadedxe2x80x9d from the ramp onto the disk. As the slider approaches the disk surface, an air cushion is generated by the disk""s rotation. The slider can also be xe2x80x9cunloadedxe2x80x9d from the disk""s surface onto the ramp. In this manner, the slider is positioned over the disk without substantial contact with the disk surface. By reducing the contact between the slider and the disk surface, the interface life can be increased. Nonetheless, even with the load/unload system""s reduced contact, the system still risks the dangers cited above because there is frequently some slider/disk contact during start and stop, there is always slider/ramp contact when the spindle motor is powered down, and there is a possibility of more harmful contact if a bumpy load or unload occurs.
In order to reduce the risks cited above as well as properly position the slider (transducer) above the disk surface, manufacturers of the systems often burnish the sliders before assembly. For instance, burnishing has been performed during manufacture in order to obtain a thin-film head slider with stable flying characteristics and good running durability. This is accomplished by polishing the medium-facing slider surface, which constitutes the air bearing surface. Such burnishing decreases the flying height of the slider and evens the air bearing surfaces by wearing flat and burning-in the slider""s air bearing surfaces. Similarly, such burnishing or pre-conditioning of the sliders reduces the likelihood of disk or slider damage because the process removes sharp protrusions and rounds sharp comers significantly reducing the stress imparted on to the disk by the slider and vice versa. Japanese Patent Public Disclosure No""s. Sho 60-185272, Sho 63-70918, Hei 2-199614, Hei 2-212057, Hei 2-301014 disclose polishing films and polishing tapes used during manufacture to polish the air bearing surfaces of sliders. Similarly, a method of preliminary burnishing of contact type magnetic heads during manufacture has been proposed in U.S. Pat. No. 5,887,336. Yet, this proposal only addresses burnishing contact type heads by using an non-lubricated area covering the full circumference of the disk during manufacturing or prior to a normal recording and reproducing.
Unfortunately, pre-conditioning contact sliders or air bearing sliders during manufacture can not cure problems that occur as a result of slider/disk contact that happens after manufacture. Furthermore, burnishing of air bearing sliders during manufacturing creates numerous other setbacks. First, because all air bearing sliders are assumed to burnish at about the same rate, those sliders that require significantly less or more burnish time will have degraded flying characteristics due to excessive or insufficient burnishing. Out of a batch of sliders, this portion can be significant. Second, this approach assumes that the burnishing occurs only initially, when the sliders are conditioned during manufacture, when in fact, burnishing might occur as a result of slider disk contact at any time resulting in incorrect flying height. In particular, if additional burnishing occurs, the flying height of the heads may be too high to allow reading of previously written data, resulting in hard read errors. Finally, over burnishing after system assembly utilizing the disk surface can burn through the air bearing pads, exposing harder, rougher, and/or more jagged structure. This will disturb the overall disk surface by causing scratches, debris trails, carbon wear tracks, or other deleterious effects that may cause a crash, impact long term slider flyability, or deter from disk surface life.
Disk drives that crash or are seriously damaged during use are infrequently repaired due to repair costs which usually exceed the value of the drive. Furthermore, expensive data and time can be lost when the drive goes bad.
Therefore, there is a need for the ability to monitor burnishing during manufacture to avoid over or under-burnishing. Similarly, there is a need for the ability to burnish after manufacture to prevent crashes and extend system life by removing uneven surfaces, protrusions, and debris that develop in systems after manufacture. Moreover, the ability to burnish during the life of the system will allow users to repair incorrect slider flying height which will increase system performance and life.
It is a primary object of the present invention to provide means to burnish the slider after manufacture to prevent crashes and extended system life by removing uneven surfaces, protrusions, and debris that develop in systems after manufacture.
Another object of the present invention is to provide means to burnish during the life of the system will allow users to repair incorrect slider flying height which will increase system performance and life.
In accordance with a primary aspect of the present invention a magnetic data storage system comprises a storage disk having a data surface of concentric radial tracks and a burnishing track, means for rotating said disk, and at least one slider having an air bearing surface for air support of said slider over said data surface, wherein said burnishing track is a dedicated track for burnishing said slider.
Another aspect of the present invention is that the burnishing track is segmented into at least one burnishing zone and at least one monitoring.

Dedicated disk burnishing zones for burnishing magnetic recording sliders

International Business Machines Corporation


A high frequency oscillator comprises a transmission line resonator having a midpoint which serves as a null potential point, a pair of active devices for oscillation respectively connected to a pair of mutually opposite-phase resonance wave points for the transmission line resonator, and a plurality of output lines each having one end connected to the transmission line resonator at a point symmetric to the midpoint, and the other end commonly connected to a connection. The pair of active devices share the resonator and oscillate in opposite phases to each other. The plurality of output lines are coupled to the transmission line resonator respectively at maximum displacement distribution points for a standing wave of an 2n-th harmonic in the transmission line resonator, where n is an integer equal to or larger than two. Even-order harmonic components of 2(n−1)-th or lower are suppressed at the connection.

1. Field of the Invention
The present invention relates to a high frequency oscillator for oscillating signals in a millimeter-wave band and a microwave band, and more particularly, to a high frequency oscillator which employs a transmission line resonator and is suitable for generation of a frequency four times or more higher than a fundamental oscillation frequency (i.e., fundamental wave) based on the resonator.
2. Description of the Related Art
High frequency oscillators suitable for generating oscillation signals in a millimeter-wave band and a microwave band are employed, for example, in optical communication systems and peripheral apparatuses associated therewith, and are required to improve the performance and reduce the cost. The present inventors have previously proposed such a high frequency oscillator which is a push-push oscillator using a transmission line resonator in Japanese Patent Laid-open Publication No. 2003-152455 (JP, P2003-152455A). This oscillator can generate signals at frequency twice or four times higher than a fundamental resonant frequency of the resonator in a simple structure. It should be noted that the push-push oscillator employs a pair of oscillation circuits which operate at the same fundamental frequency and in opposite phases to each other, and combines outputs of these oscillation circuits to cancel out fundamental wave components and extract even-order harmonic components to the outside.
FIG. 1 is a plan view illustrating the configuration of a conventional second-harmonic oscillator for generating a second harmonic signal which is a signal at a frequency twice as high as a fundamental resonant frequency of the oscillator.
This high frequency oscillator comprises transmission line resonator 1, active devices 2 for oscillation, and an output line 3. Transmission line resonator 1 is microstrip line resonator 1A comprised, for example, of a microstrip line, and has an elongated signal line routed on one principal surface of dielectric substrate 4. A ground conductor is disposed substantially over the entirety of the other principal surface of dielectric substrate 4. Microstrip line resonator 1A has a length of, for example, λ/2, where λ is the wavelength corresponding to a fundamental frequency (fundamental wave f0) of oscillation.
Each of active devices 2 for oscillation is comprised, for example, of FET (Field Effect Transistor) 2A. In the illustrated oscillator, FETs 2A are disposed at both ends of microstrip line resonator 1A, respectively. Each FET 2A has a gate connected to a corresponding end of microstrip line resonator 1A through capacitor 5 for providing loose coupling. By thus connecting the gates of FETs 2A, microstrip line resonator 1A has resonant wave points (i.e., antinodes or nodes of a standing wave) at both ends.
The gate of each FET 2A is applied with a bias voltage through another microstrip line, not shown. Each FET 2A has a drain connected to microstrip line 6a which is designed to provide a negative resistance, and supplied with an operating voltage from a power supply, not shown. Each FET 2A has a source grounded. Microstrip line 6a is configured to have an electrically open end, when viewed from the drain, with respect to the fundamental oscillation frequency.
Output line 3, which has a microstrip line structure, is connected to a midpoint of microstrip line resonator 1A in the longitudinal direction through capacitor 5 for providing loose coupling. It should be noted that by loosely coupling output line 3 and FETs 2A to microstrip line resonator 1A, microstrip line resonator 1A is improved in independence, and is prevented from being affected by FETs 2A and output line 3. Connected at a midpoint of microstrip line 1 is microstrip line 6b which has a length of λ/4, and an open distal end. This microstrip line 6b, which is a so-called quarter wavelength stub, functions as an electrically short-circuited point with respect to a fundamental wave component f0, when viewed from a point at which it is connected to the resonator.
In this high frequency oscillator, equivalently, active devices 2, each comprised of FET 2A and having a negative resistance, are connected to both ends of microstrip line resonator 1A through electric field coupling. Therefore, for example, as illustrated in FIG. 2, a standing wave of fundamental wave f0 is generated with a null potential point located at the midpoint of microstrip line resonator 1A, and maximum displacement distribution points located at both ends of microstrip line resonator 1A which are resonant wave points, at which the standing wave is in an opposite phase relationship to each other. Also, other standing waves are generated corresponding to n-th harmonic n×f0 of fundamental wave f0, where n is an integer equal to or larger than two. In FIG. 2, the standing wave of fundamental wave f0 is represented by a solid line; a standing wave of second harmonic wave 2f0 is represented by a broken line; and a standing wave of third harmonic wave 3f0 is represented by a one-dot chain line. Among these standing waves, fundamental wave f0 has the highest level, and the level becomes lower as harmonics have higher order numbers.
In the foregoing configuration, since the negative resistive devices (FETs 2A) are disposed at both ends of microstrip line resonator 1A, i.e., resonant wave points, there are formed two oscillation systems which share the microstrip line resonator for fundamental wave f0 and higher-harmonics n×f0 components. Since both ends of microstrip line resonator 1A are reverse-level potential points to each other in the oscillation system associated with fundamental wave f0, the two oscillation systems oscillate in opposite phases to each other. Then, since output line 3 is connected to the midpoint of microstrip line resonator 1A, which is an electrically short-circuited point, i.e., a null potential point with respect to fundamental wave f0, fundamental wave f0 is not delivered from output line 3. Also, for third harmonic or higher harmonic components (2n−1)×f0, i.e., odd-order harmonics of fundamental wave f0, the midpoint of microstrip line resonator 1A serves as a null potential point, thus preventing these harmonic components from being delivered from output line 3, in a manner similar to fundamental wave f0.
The standing wave of second harmonic 2f0 relative to fundamental wave f0, has maximum displacement distribution points at the midpoint and both ends of microstrip line resonator 1A at which the standing wave is in opposite phases to each other. Since output line 3 is connected to such a midpoint, second harmonic 2f0 is generated at output terminal fout which is the other end of output line 3. In this way, the high frequency oscillator can provide an oscillation frequency which is twice higher than fundamental wave f0.
A standing wave of fourth or more even-order harmonic 2n×f0 also has a maximum displacement distribution point at least at the midpoint of microstrip line resonator 1A, and is in opposite phase or in phase to the midpoint at both ends. As a result, a fourth or more even-order harmonic is similarly generated from output line 3, but has an output level relatively low as compared with the second harmonic component.
FIG. 3 illustrates the second-harmonic oscillators, illustrated in FIG. 1, arranged in parallel on the same substrate 4, and a microstrip line (first output line 3A) having a length of λ/4, where λ is the wavelength of fundamental wave f0, disposed between the second-harmonic oscillators. First output line 3A has one end connected to a midpoint of microstrip line resonator 1A through capacitor 5 for loose coupling, and the other end connected to a midpoint of the other microstrip line resonator 1A through capacitor 5 for loose coupling. In other words, first output line 3A has a length equivalent to one-half wavelength with respect to a second harmonic component 2f0, and connects the midpoints of both microstrip line resonators 1A to each other. Further, second output line 3B is connected to a midpoint of first output line 3A through capacitor 5 for loose coupling. Further connected at the midpoint of each microstrip line 1A is microstrip line 6b which has an open distal end, but unlike the one illustrated in FIG. 1, microstrip line 6b has a length of λ/8, which is one quarter of the wavelength of second harmonic 2f0 wave.
In the foregoing configuration, second harmonic 2f0 is delivered to first output line 3A from each second-harmonic oscillator, while fundamental wave f0 is suppressed. Then, first output line 3A functions as a half-wavelength resonator for second harmonic 2f0, and similar to the foregoing case, the midpoint of first output line 3A serves as a null potential point with respect to the standing wave of second harmonic 2f0. On the other hand, the midpoint of first output line 3A serves as a maximum displacement distribution point for the standing wave of fourth harmonic 4f0. For this reason, a second harmonic 2f0 component is also suppressed, so that fourth harmonic 4f0 and higher even-order components are only generated on second output line 3B. In this event, since fourth harmonic component 4f0 is prominent among other even-order harmonic components, the circuit illustrated in FIG. 3 functions as a fourth-harmonic oscillator for generating the fourth harmonic, which has a frequency four times as high as that of fundamental wave f0.
As described above, it is possible to implement a high frequency oscillator for generating 2n-th harmonic component 2n×f0, where n is an integer equal to or larger than two, by repeatedly combining two high frequency oscillators for generating a lower order harmonic to form a higher-order harmonic oscillator.
While microstrip line resonator 1A has been described to be linear in the foregoing discussion, the oscillator also operates in a similar manner when microstrip line resonator 1A is formed into an annular or ring shape.
The high frequency oscillators configured as described above, however, have the following problems.
Basically, a second-harmonic oscillator can be made up of one microstrip line resonator 1A having a length of λ/2, and two negative resistive devices at both ends thereof, where λ is the wavelength corresponding to the fundamental frequency of oscillation, i.e., fundamental wave f0. However, since a fourth-harmonic oscillator requires a pair of second-harmonic oscillators which cause the resulting oscillator to be large in size, and therefore hampers a reduction in size of the oscillator. Likewise, for providing a 2n-th harmonic oscillator for generating an eighth harmonic or a higher-order harmonic (n≧3), a pair of 2(n−1)-th harmonic oscillators are required, and further hamper a reduction in size of the oscillator.

High frequency oscillator using transmission line resonator


A lithium ion secondary battery includes: a positive electrode including a positive electrode active material; a negative electrode formed by coating a negative electrode active material mixture onto a surface of a negative electrode collector, the negative electrode active material mixture including a negative electrode active material, a conductive additive, and a binder; a separator interposed between the positive electrode and the negative electrode; and an electrolyte, in which the negative electrode active material includes graphite and an Si alloy, inequities of 0.43≦x≦9.0 and 8≦y<18 are satisfied when a mass ratio of the graphite and the Si alloy is defined as x and a coating amount of the negative electrode active material mixture is defined as y (mg/cm2). Thus, an initial capacity thereof can be increased and a capacity retention rate thereof can be improved in the lithium ion secondary battery which includes the Si alloy in the negative electrode.

1. Field of the Invention
The present invention relates to a lithium ion secondary battery.
2. Description of the Related Art
In recent years, lithium ion secondary batteries have been noted particularly as secondary batteries having high energy density, and their research, development, and commercialization have been progressed rapidly. At present, lithium ion secondary batteries have been generally popularized as small-sized domestic use for mobile phones and notebook personal computers. Further, large-scale secondary batteries of higher capacity than usual have been demanded as batteries for domestic, industrial, on-board uses etc. in view of problems or issues such as global warming, fuel exhaustion, and denuclearization.
As measures of increasing the capacity of the lithium ion secondary batteries, it has been known to use silicon (Si) or Si-containing compounds for negative electrode materials. However, Si involves a problem in view of rate characteristics since Si has a powder resistance which is two orders of magnitude higher than that of graphite. Further, increase of the coating amount of the electrode has not been investigated since Si involves a problem in the cycle life.
JP-2008-277232-A describes use of a negative electrode material for a lithium secondary battery, the negative electrode material disposing carbonaceous material particles containing at least one element selected from graphite and carbon black on surfaces of composite particles containing graphite particles, fine Si particles and amorphous carbon (A), in which the carbonaceous material particles are coated with amorphous carbon (B), in order to increase initial charge/discharge capacity and improve charge/discharge cycle characteristics of the lithium secondary battery. The configuration described above can moderate a volume change of the fine Si particles and maintain an electric contact of the active material during charge/discharge, thereby improving charge/discharge cycle characteristics.


A carton, typically of corrugated paperboard, is formed from a one-piece blank having major side wall bottom flaps and minor end wall bottom flaps arranged to be securely interlocked, for which purpose openings which comprise or include slits are provided preferably in the major side wall bottom flaps into which may be inserted tabs preferably on the corners of the minor end wall bottom flaps. The tabs are shaped so as to provide hooks which engage exposed edges of the slits to lock and prevent the tabs from being accidentally withdrawn after insertion, thus providing a carton with a locked bottom closure.

In the fruit growing industry, particularly that which involves the production of relatively heavy fruit items such as melons, grapefruit and cantaloupe, there is a continuing need for a paperboard carton or container which has a bottom which may be formed from the flap parts of the carton blank with the flap parts interrelated in such a way that they may be quickly and securely locked together in the usual container hand-forming process without gluing, stapling, or other extraneous mechanical means.
For this purpose there have been developed various forms of carton parts including side wall and end wall bottom flaps which have various forms of tabs which can be inserted into openings in related flaps which are arranged to receive them. Examples are afforded by U.S. Pat. No. 5,104,035 issued to Booth and Austrian Patent 218,420 issued in 1961 to Stoklasek. But nothing has been done adequately to interlock the flaps and their respective tabs in place relative to each other by means provided solely by the shapes of the various parts and without the need or use of extraneous fastening means.
Accordingly the primary object of this invention is to provide a one-piece carton blank formed and arranged in such manner that when the blank is assembled into a carton the bottom parts may be easily brought together and securely locked so that accidental withdrawal and disassembly is prevented in spite of any weight of the contents or rough handling of the cartons in transportation and use and so that any intended disassembly can only be accomplished by careful manipulation of the parts.


A method is disclosed for operating an internal combustion engine of the type having an engine cylinder with a reciprocating piston, first and second intake ports for admitting gas from an ambient air supply into the engine cylinder, first and second intake valves each arranged between a respective one of the intake ports and the engine cylinder, a non-return valve arranged in the second of the intake ports at a distance from the second intake valve and oriented to allow gas to flow only towards the engine cylinder, and a variable valve actuating system for controlling the opening and closing of at least the second intake valve. In the method of the invention, in at least one operating mode of the engine, the second intake valve is opened and closed, while the cylinder is fully isolated from the ambient air, to permit gas transfer between the cylinder and an auxiliary chamber temporarily defined by the part of the second intake port lying between the second intake valve and the non-return valve. The second intake valve is opened at a time when the pressure in the auxiliary chamber is greater than the pressure of the ambient air supply such that no gas escapes past the non-return valve.

It is known to provide an auxiliary chamber which is connected and disconnected with an engine cylinder during the compression or expansion period of the engine cycle in order to influence the compression or expansion process. EP0095252 proposes using such an auxiliary chamber to trap a variable fraction of the cylinder charge during compression in order to vary the effective compression ratio of the engine. Pending patent application PCT/GB2004/001018 proposes using an auxiliary chamber as a buffer chamber in an air hybrid engine vehicle to transfer compressed gases in two steps via the auxiliary chamber to a compressed gas reservoir when the engine is operating as a gas compressor thereby assisting deceleration of the vehicle, and to expand the compressed gases in two steps from the compressed gas reservoir via the auxiliary chamber when the engine is operated as a gas expander thereby assisting acceleration of the vehicle. Another pending patent application GB0405828.5 proposes using an auxiliary chamber to vary the compression temperature of the cylinder charge in order to achieve CAI/HCCI combustion and influence the auto-ignition timing.
In order to apply the above proposed concepts, it has hitherto been necessary to provide a dedicated auxiliary chamber and a dedicated control valve connecting with the engine cylinder at the appropriate timing in order to vary the internal gas transfer. Such a system however adds cost and complexity, and is difficult to install in the limited space of the combustion chamber of the engine.

Method of operating an internal combustion engine