The present invention provides a method for detecting the presence of a target polynucleotide in a sample. The method comprises the steps of (a) contacting the sample under hybridizing conditions with (i) a single-stranded polynucleotide probe capable of hybridizing to the target polynucleotide and comprising a polynucleotide and at least one intercalating molecule attached to a nucleotide of the polynucleotide by means of a linker arm, and (ii) a background-reducing reagent which chemically modifies the intercalating molecule when the probe to which it is attached is single-stranded; and (b) detecting a property change resulting from the intercalation of the intercalating molecule into a target-probe hybrid, thereby detecting the target polynucleotide. The intercalating molecule which is part of the polynucleotide probe induces a change in a property, in either the probe, the target polynucleotide or a target-probe hybrid. The property change can be detected, for example, by means of a generated signal which can be identified or quantified. The present invention can be employed in a heterogeneous (two step or two phase) assay using a support to immobilize the target or probe, and a washing step, and in a homogeneous (one step or one phase) assay using a hybridization solution. Also provided are a composition and a nucleic acid hybridization kit useful for detecting the presence of a target polynucleotide in a sample.

Polynucleotide hybridization assays using a polynucleotide probe for verifying the presence of a target polynucleotide analyte are well known in the art. Hybridization is based on complementary base-pairing between target and probe sequences. The quantity of the polynucleotide probe, as compared to the target polynucleotide, is in excess with ratios of 6:1 of probe per target, or greater being employed conventionally. Furthermore, the amount of the probe which hybridizes to the target is typically a fraction, 0.1%. Therefore, it is very desirable to quench the fluorescence of the unhybridized probe so that minute quantities of the polynucleotide probe hybridized to the target can be accurately detected.
In U.S. application Ser. No. 06/808,757, now abandoned, a homogeneous assay method is disclosed in which a polynucleotide probe is used to detect the presence of a target polynucleotide in a sample. Much of the contents of U.S. application Ser. No. 06/808,757, now abandoned has already been published. See, e.g., corresponding European Patent Application Publication No. 231,495, published on Aug. 12, 1987.
The disclosed probe comprises a polynucleotide and at least a first entity and a second entity. The first entity is attached to a first nucleotide of the polynucleotide by means of a linker arm, separated by about ten nucleotides from the second entity which is attached to a second nucleotide, also by means of a linker arm. Upon hybridization of the probe to the target polynucleotide, the entities, by virtue of their characteristics, e.g., the ability to intercalate into a target-probe hybrid, provide for a property change in either the probe, the target, or both. The change in property can be detected by appropriately measuring an associated signal, e.g., radiation emission, interaction of molecular dispersion forces, such as melting temperature, and buoyant density.
It has now been discovered that the signal intensity in a hybridization assay can be significantly enhanced by contacting the hybridization reaction mixture with a background- reducing reagent which chemically modifies the intercalating groups, e.g., of an aromatic dye, when the probe to which these intercalating groups are attached remains unhybridized to target. By modifying the intercalating groups in this way, interfering signal from the unhybridized single-stranded probe can be reduced significantly, if not altogether eliminated.

Methods for detecting a polynucleotide using an inactivating reagent and composition and kit comprising same


A fuel cell provides a high output at a high current density. The fuel cell has an anode electrode and a cathode electrode comprising a gas diffusion layer, a water-repellent layer disposed on the gas diffusion layer and containing a carbon material and polytetrafluoroethylene, and an electrode catalyst layer disposed on the water-repellent layer and containing a carbon material carrying a catalyst. The electrode catalyst layer has maximum and minimum thicknesses that differ from each other by less than 30 μm. The electrode catalyst layer has cracks whose area is less than 10% of a total area of the electrode catalyst layer.

1. Field of the Invention
The present invention relates to an electrode for a fuel cell which is capable of achieving a high output at a high current density, a method of manufacturing such an electrode, and a fuel cell having such an electrode.
2. Description of the Related Art
FIG. 9 of the accompanying drawings shows in vertical cross section a unit cell of a general phosphoric acid fuel cell which is one of presently available fuel cells. The unit cell, denoted at 1, has an electrolyte electrode assembly 5 which comprises an anode electrode 2, a cathode electrode 3, and an electrolyte 4 interposed between and joined to the electrodes 2, 3.
The electrolyte 4 comprises a polymer membrane made of a basic polymer such as polybenzimidazole and impregnated with a liquid electrolyte. See U.S. Pat. No. 5,525,436 for details. The liquid electrolyte may, for example, be phosphoric acid, sulfuric acid, methanesulfonic acid, or the like which conducts hydrogen ions.
As shown in FIG. 10 of the accompanying drawings, the anode electrode 2 and the cathode electrode 3 comprise respective gas diffusion layers 6a, 6b and respective electrode catalyst layers 7a, 7b coated uniformly on respective surfaces of the gas diffusion layers 6a, 6b. Generally, the gas diffusion layers 6a, 6b are made of carbon paper, carbon cloth, or the like, and the electrode catalyst layers 7a, 7b are made of a carbon black with a catalyst of Pt carried on its particle surface, or the like.
As shown in FIG. 9, the electrolyte electrode assembly is interposed between two separators 8a, 8b. The unit cell 1 also has collector electrodes 9a, 9b held against respective outer surfaces of the separators 8a, 8b, and end plates 10a, 10b held against respective outer surfaces of the collector electrodes 9a, 9b. The end plates 10a, 10b are connected to each other by bolts (not shown), sandwiching the electrolyte electrode assembly 5, the separators 8a, 8b, and the collector electrodes 9a, 9b between the end plates 10a, 10b. The separators 8a, 8b have respective gas passages 11a, 11b defined therein for supplying a hydrogen-containing gas and an oxygen-containing gas to the anode electrode 2 and the cathode electrode 3.
The anode electrode 2, the cathode electrode 3, and the electrolyte 4 are accommodated respectively in frame-shaped seals 12, 13, 14.
The general phosphoric acid fuel cell comprises a stack (not shown) of unit cells 1 that are electrically connected in series, a mechanism for supplying a hydrogen-containing gas to and discharging a hydrogen-containing gas from the stack, and a mechanism for supplying an oxygen-containing gas to and discharging an oxygen-containing gas from the stack.
For operating the phosphoric acid fuel cell, a fuel gas such as a hydrogen-containing gas or the like is supplied via the gas passages 11a in the separator 8a to the anode electrode 2 of each unit cell 1, whereas an oxygen-containing gas such as air or the like is supplied via the gas passages 11b in the separator 8b to the cathode electrode 3. The fuel gas and the oxygen-containing gas pass through the respective gas diffusion layers 6a, 6b of the electrodes 2, 3 and then reach the respective electrode catalyst layers 7a, 7b. In the electrode catalyst layer 7a of the anode electrode 2, the hydrogen in the fuel gas causes a reaction represented by the following formula (A), generating hydrogen ions and electrons:2H2→4H++4e  (A)
The generated hydrogen ions move through the electrolyte 4 to the cathode electrode 3. During this time, the electrons flow to an external circuit that is electrically connected to the anode electrode 2 and the cathode electrode 3, are used as an electric energy in the form of a direct current to energize the external circuit, and then flow to the cathode electrode 3.
The hydrogen ions that have moved to the cathode electrode 3 and the electrons that have moved to the cathode electrode 3 via the external circuit react with the oxygen contained in the oxygen-containing gas supplied to the cathode electrode 3, as indicated by the following formula (B):O2+4H++4e→2H2O  (B)
The fuel gas which remains unreacted is discharged out of the unit cell 1 (fuel cell) through the gas passages 11a in the separator 8a. Similarly, the oxygen-containing gas which remains unreacted and the generated H2O are discharged out of the unit cell 1 through the gas passages 11b in the separator 8b.
If the voltage across the unit cell 1 is represented by V, the density of the current generated by the unit cell 1 by I, and the effective area of the electrodes 2, 3 by S, then the output P of the unit cell 1 is determined according to the following equation (C):P=I×V×S  (C)
In the fuel cell, as the current density I increases, the cell voltage V drops, and finally the output P of the unit cell 1 drops, as can be seen from the equation (C). Specifically, when the fuel cell generates electricity at a large current density, the voltage across the fuel cell drops below a desired level, failing to sufficiently energize the load connected to the fuel cell. For this reason, there has been a demand for a unit cell whose voltage drop is lower even when it generates electricity at a large current density, i.e., whose output is large at a large current density.
While the cell voltage V across the unit cell 1 varies depending on the current density I, the cell voltage V is generally about 1 V. If a higher cell output is needed to provide a power supply for a motor on an automobile, for example, then it is necessary to connect a number of unit cells 1 in series. However, the resulting fuel cell increases in weight and size, requiring a large installation space on the automobile. The automobile with the fuel cell carried thereon also becomes heavy. To avoid these shortcomings, there has been a demand for a unit cell with a higher output.
For increasing the cell voltage V at the time the unit cell is discharged at a high current density, it is necessary to reduce the internal resistance of the unit cell 1.
As can be understood from the formula (B), H2O is generated during operation of the fuel cell. The amount M (mol/min.) of H2O generated per unit time is determined from the current density I (A/cm2) and the effective electrode area S (cm2) according to the following equation (D):M=I×S×60/(96500×2)  (D)
Thus, the amount M of H2O generated per unit time increases as the current density I increases. In continued operation of the fuel cell under this condition, when the generated H2O is discharged, the liquid electrolyte of phosphoric acid or the like seeps from the composite electrolyte 4, tending to clog the interstices of the gas diffusion layer 6b (carbon paper or the like). When the interstices of the gas diffusion layer 6b clogged, it is difficult for the supplied oxygen-containing gas to be diffused to the electrode catalyst layer 7b, making it difficult for the reaction represented by the formula (B) to take place. Stated otherwise, since the reaction efficiency of the reaction represented by the formula (B) is lowered, the cell voltage of the unit cell drops.
Japanese laid-open patent publication No. 60-170168 proposes a water-repellent layer interposed between a gas diffusion layer and an electrode catalytic layer for repelling a liquid electrolyte to prevent the liquid electrolyte from seeping from an electrolyte.
The water-repellent layer is produced by coating a gas diffusion layer of carbon paper or the like with a solution which has been prepared by dissolving a porous carbon material and PTFE (polytetrafluoroethylene) in a solvent such as water, isopropyl alcohol, or the like, and heating the coated gas diffusion layer preferably at a temperature ranging from 350 to 400° C. to harden the coated solution.
However, the water-repellent layer thus produced tends to crack easily to the extent that the produced cracks usually reach about 5%, or about 15% at maximum, of the total area of the water-repellent layer. The water-repellent layer itself may suffer surface irregularities and have maximum and minimum thicknesses that differ from each other by at least 60 μm. When the coated gas diffusion layer is heated in the above temperature range, the water-repellent layer becomes too water-repellent to allow an electrode catalyst layer paste to be easily coated on the gas diffusion layer. An electrode catalyst layer somehow coated on the gas diffusion layer also tends to crack and suffer surface irregularities. The cracks in the electrode catalyst layer usually reach about 10%, or about 30% at maximum, of the total area of the electrode catalyst layer. The electrode catalyst layer with surface irregularities has maximum and minimum thicknesses that differ from each other by about 50 μm.
The crack in the electrode catalyst layer obstructs electric conduction in the electrode catalyst layer. The electrode catalyst layer with the surface irregularities suffer an irregular charge distribution. At any rate, the electric conductivity of the electrodes is lowered, resulting in an increase in the internal resistance of the fuel cell.
As described above, when the fuel cell is operated to generate electricity at a high current density, the liquid electrolyte seeps from the composite electrolyte. The water-repellent layer added to prevent the liquid electrolyte from seeping from the composite electrolyte invites an increase in the internal resistance of the fuel cell. Consequently, it is highly difficult to construct a fuel cell which is capable of achieving a high output at a high current density.

Electrode for fuel cell, method of manufacturing same, and fuel cell with such electrode


Described are methods and systems of processing three-dimensional (“3D”) data by generating an edge map, a depth map, or both. Data points are placed into a bin array based their respective image coordinates. The data points in each bin are processed to determine edge data. An edge map may be generated from this edge data. A bin value may be generated based on the data points in each bin, and a depth map generated using these bin values. The edge data and the edge map may be processed using one or more filter functions. Measurements based on the edge map may be provided at a resolution greater than that available with the depth map.

Three-dimensional ("3D") scans of actual objects may result in generation of large sets of data. These large sets of data may be processed in various ways to identify the actual object, determine one or more dimensions or measurements of the actual object, and so forth. The processing may be computationally complex to execute, particularly on devices with limited computing resources, such as portable computing devices.
Certain implementations and embodiments will now be described more fully below with reference to the accompanying figures, in which various aspects are shown. However, various aspects may be implemented in many different forms and should not be construed as limited to the implementations set forth herein. Like numbers refer to like elements throughout.


An air bag system includes a cushion expanded to the front of a passenger by means of gas discharged from an inflator when a collision of the vehicle occurs for absorbing shock transmitted to the passenger. The cushion comprises a main panel having an inlet part formed at one side thereof for allowing the gas discharged from the inflator to be introduced into the cushion therethrough, side panels attached to both open sides of the main panel by means of sewing, respectively, and a tether having one end fixed to the inlet part of the main panel by means of sewing and the other end fixed to the inner side of the panel opposite to the inlet part of the main panel while not intersecting with the parts where the main panel and the side panels are sewn.

1. Field of the Invention
The present invention relates to an air bag system mounted in a vehicle, and more particularly to a cushion for air bag systems which is capable of preventing breakage of sewn parts of the cushion caused by means of expansion pressure of the cushion when a collision of the vehicle occurs.
2. Description of the Related Art
Generally, an air bag system for vehicles is mounted in front of a driver seat or a passenger seat in such a manner that a cushion of the air bag system is instantly expanded when a collision of the vehicle occurs for protecting a driver or a passenger from injury.
The air bag systems may be classified into a driver air bag system and a passenger air bag system. The driver air bag system is mounted to the steering wheel of the vehicle for protecting the driver from injury. The passenger air bag system is mounted to an instrument panel of the vehicle disposed in front of the passenger seat for protecting the passenger from injury. Basically, the driver air bag system is requisite, and the passenger air bag system is optional; however, vehicles with passenger air bag systems basically mounted therein for protecting passengers from injury are on the increase in recent years.
FIG. 1 is a cross-sectional view showing a passenger air bag system according to the conventional art, FIG. 2 is a perspective view showing the passenger air bag system according to the conventional art, FIG. 3 is a perspective view showing a cushion of the passenger air bag system according to the conventional art, and FIG. 4 is a plan view showing an inlet part of the cushion of the passenger air bag system according to the conventional art.
As shown in FIGS. 1 and 2, the conventional passenger air bag system for vehicles comprises: an air bag housing 4 mounted in an instrument panel 2; an inflator 6 attached to the air bag housing 4 for discharging gas when a collision of the vehicle occurs; a retainer 8 attached to the inside of the air bag housing 4 and having a plurality of gas-discharging holes for discharging gas from the inflator 6; and a cushion 10 accommodated in the air bag housing 4 such that the cushion 10 is expanded toward a passenger seat by means of gas discharged through the air-discharging holes of the retainer 8, the cushion 10 being fixed to the retainer 8 at one side thereof.
The air bag housing 4 comprises: a cushion housing 12 attached to the rear part of the instrument panel 2, the cushion housing 12 being formed in the shape of a box with the front part opened so that the cushion 10 is accommodated in the cushion housing 12; and a can housing 14 connected to the rear part of the cushion housing 12, wherein the inflator 6, which supplies high-pressure gas to the cushion 10 when a collision of the vehicle occurs, is disposed in the can housing 14.
The cushion housing 12 is provided at both longitudinal sides thereof with flanges 12a, respectively, which are fixed to the instrument panel 2 by means of bolts. The can housing 14 is provided at the outside thereof with a mounting bracket 16, which is fixed to a cowl cross member 18 by means of a bolt.
The inflator 6 is connected to a collision-detecting sensor (not shown) for detecting a collision of the vehicle so that the inflator 6 is exploded by means of a signal outputted from the collision-detecting sensor when the collision of the vehicle occurs. The cushion 10 is expanded toward the front of the cushion housing 12 by means of gas having a prescribed pressure, which is generated from the explosion of the inflator 6.
The instrument panel 2 is broken along a cut line 2a formed at the instrument panel 2 by means of the cushion 10 expanded as described above. Consequently, the cushion 10 is expanded toward the passenger seated in the passenger seat of the vehicle.
As shown in FIGS. 3 and 4, the cushion 10 comprises: a main panel 22 formed in the shape of a cylinder and having an inlet part 20 formed at one side thereof, the inlet part 20 of the main panel 22 being fixed by means of the retainer 8; side panels 24 attached to both open sides of the main panel 22 by means of sewing, respectively; and a tether 26 having one end fixed to the inlet part 20 of the main panel 22 and the other end fixed to the inner side of the panel 22, which is opposite to the inlet part 20 of the main panel 22.
The main panel 22 is formed in such a manner that a long strip is rolled in the shape of a cylinder and then stitched. The main panel 22 is the front part of the cushion 10, which approaches a passenger when the cushion 10 is expanded. To the sides of the main panel 22 are attached the side panels 24 by means of a first sewing part 28, respectively.
Each of the side panels 24 has a ventilation hole 24a formed at a prescribed part thereof for discharging gas introduced into the cushion 10 to the outside. When the passenger contacts the cushion 10 due to the impact caused when a collision of the vehicle occurs, the gas in the cushion 10 is discharged to the outside through the ventilation hole 24a so that shock transmitted to the passenger is effectively absorbed.
The tether 26 is formed in the shape of a long strip. One end of the tether 26 is fixed to the inlet part 20 of the main panel 22 by means of a second sewing part 30. The other end of the tether 26 is fixed to the inner side of the front part of the main panel 22 opposite to the inlet part 20 of the main panel 22, by which the shape of the expanding cushion 10 is determined.
One end of the tether 26 with the above-stated construction is fixed to the inlet part 20 of the main panel 22 so that the tether 26 forms the inlet part 20 together with the main panel 22. The inlet part 20 of the main panel 22 is provided at the center thereof with a gas-introducing hole 20a, which communicates with the gas-discharging holes of the retainer 8 for introducing the gas discharged from the inflator 6 into the cushion 10. Around the gas-introducing hole 20a formed at the inlet part 20 of the main panel 22 are formed a plurality of fixing holes 20b, through which the inlet part 20 of the main panel 22 is attached to the can housing 14 along with the retainer 8 by means of bolts.
Especially, one end of the tether 26 is formed with the same width as the inlet part 20. Both sides of the tether 26 are sewn with the main panel 22 and the side panels 24, by which the first sewing part 28 is formed. The second sewing part 30 is formed in the lateral direction of the tether 26 so that the first and second sewing parts 28 and 30 intersect each other at both sides A of one end of the tether 26.
Alternatively, one end of the tether 26 may be fixed to the main panel 22 by means of sewing while not forming the inlet part 20 together with the main panel 22. In this case, it is required to attach a plurality of additional reinforcing cloths to the main panel 22 so that the strength of the inlet part 20 is increased.
Preferably, the tether 26 and the main panel 22 together form the inlet part 20. Consequently, durability and thermal resistance of the inlet part 20 are increased by means of the tether 26, which requires no reinforcing cloths or only a reduced number of reinforcing cloths.
The operation of the conventional passenger air bag system with the above-stated construction will now be described. When a collision of the vehicle is detected by means of the collision-detecting sensor, a signal outputted from the collision-detecting sensor is transmitted to the inflator 6 so that the inflator 6 is exploded to generate gas.
The gas generated by means of the inflator 6 flows along the air bag housing 4 so that the gas is supplied to the gas-discharging holes of the retainer 8 and the inlet part 20 of the cushion 10. The gas supplied to the inlet part 20 is introduced into the cushion 10 through the gas-introduction hole 20a.
Consequently, the cushion 10 is expanded to the front of the passenger seat at prescribed pressure and speed by means of the gas introduced into the cushion 10, and shock transmitted to the passenger is effectively absorbed by means of the expanded cushion 10, whereby the passenger is protected from injury when a collision of the vehicle occurs.
In the conventional passenger air bag system, however, the expanding stress of the cushion 10 is applied to the first sewing part 28, and simultaneously the stress caused from the expansion of the cushion 10 is applied to the second sewing part 30, when the cushion 10 is expanded by means of the gas discharged from the inflator 6 due to the collision of the vehicle.
At this time, the stress applied to the first sewing part 28 and the stress applied to the second sewing part 30 are concentrated at the sides A of one end of the tether 26 where the first sewing part 28 and the second sewing part 30 intersect each other.
When the stresses are concentrated at the parts A where the first sewing part 28 and the second sewing part 30 intersect each other as described above, the stress applied to the first sewing part 28 and the stress applied to the second sewing part 30 are increased with the result that the parts A where the first sewing part 28 and the second sewing part 30 intersect each other are torn when the cushion 10 is expanded. As a result, the cushion may be easily damaged.
In the case that the cushion 10 is damaged during the expansion of the cushion 10, the passenger air bag system cannot function. Consequently, shock transmitted to the passenger is not effectively absorbed when a collision of the vehicle occurs, and thus the passenger is not protected from injury.


An MR element includes a lower shield layer, a magnetization free function part stacked on the lower shield layer, an upper shield layer stacked on the magnetization free function part, a nonmagnetic intermediate layer stacked on a surface, that is opposite to a magnetically sensitive surface, of the magnetization free function part, and a magnetization fixed function part stacked on the nonmagnetic intermediate layer. The nonmagnetic intermediate layer and the magnetization fixed function part are formed only within an outer region of the magnetization free function part, located opposite side to the magnetically sensitive surface.

1. Field of the Invention
The present invention relates to a magnetoresistive effect (MR) element for reading a signal representing a magnetic field intensity in a magnetic recording medium, to a thin-film magnetic head with an MR read head element, and to a magnetic disk drive apparatus with the thin-film magnetic head.
2. Description of the Related Art
In order to satisfy demand for higher recording density and downsizing in a hard disk drive (HDD) apparatus, higher sensitivity and larger output of a thin-film magnetic head are required. In order to meet this requirement, a thin-film magnetic head with a giant magnetoresistive effect (GMR) read head element has been put to practical use and a thin-film magnetic head with a tunnel magnetoresistive effect (TMR) read head element is now achieved to come into practical use.
In the thin-film magnetic head with such GMR read head element or TMR read head element, it is now tried to more narrow a space between lower and upper shield layers, that is a read gap, of the read head element in order to attain a higher density recording.
Each of US Patent Publication No. 2004/0207960 A1 and U.S. Pat. No. 7,365,949 B2 discloses a GMR thin-film magnetic head with a decreased thickness over its whole area by extending a pinned layer toward a height direction directed opposite to the air bearing surface (ABS) so as to fix a magnetization direction of the pinned layer with the help of shape anisotropy, and by positioning a pinning layer or anti-ferromagnetic layer at the outside in the height direction of a region in which a free layer, a non-magnetic layer and the pinned layer are arranged.
However, it was insufficient to fix the magnetization direction of the pinned layer only with the help of shape anisotropy. Also, it was difficult to stably fix the magnetization direction of the pinned layer under the influence of magnetic bias from magnetic domain control layers located near the pinned layer.

Magnetoresistive effect element, thin-film magnetic head with magnetoresistive effect read head element, and magnetic disk drive apparatus with thin-film magnetic head


A compound of formula ##STR1## wherein: A is ##STR2## X is O or S; Y is O or S; G and D are independently nitrogen or carbon with the proviso that no more than one of G, D, or E is nitrogen; E is N or C-R.sub.4 ; R.sub.1 is hydrogen or methyl; R.sub.2 is hydrogen or fluoro;. R.sub.3 is hydrogen, halogen, C.sub.1 to C.sub.3 alkyl, --OR.sub.5, --CN, --CONH.sub.2, --CO.sub.2 R.sub.5, --NR.sub.5 R.sub.6 or phenyl optionally substituted with one to three of the following substituents: halogen, C.sub.1 to C.sub.3 alkyl, --NO.sub.2, --CN, or --OCH.sub.3 ; R.sub.4 is hydrogen, halogen, C.sub.1 to C.sub.3 alkyl, --OR.sub.5, --CN, --CONH.sub.2, --CO.sub.2 R.sub.5, --NR.sub.5 R.sub.6 or phenyl optionally substituted with one to three of the following substituents: halogen, C.sub.1 to C.sub.3 alkyl, --NO.sub.2, --CN, or --OCH.sub.3 ; PA0 or R.sub.2 and R.sub.3 or R.sub.4 may together represent a fused phenyl ring optionally substituted with one or two of the following substituents: halogen, C.sub.1 to C.sub.3 alkyl, --NO.sub.2, --CN, or --OCH.sub.3 ; R.sub.5 and R.sub.6 are independently hydrogen or C.sub.1 to C.sub.3 alkyl; PA0 or an enantiomer thereof, and pharmaceutically acceptable salts thereof, processes for preparing them, compositions containing them, and their use in therapy, especially in the treatment or prophylaxis of psychotic disorders and intellectual impairment disorders, as well as intermediates and use of intermediates in synthesis.

The use of compounds which bind nicotinic acetylcholine receptors in the treatment of a range of disorders involving reduced cholinergic function such as Alzheimer's disease, cognitive or attention disorders, anxiety, depression, smoking cessation, neuroprotection, schizophrenia, analgesia, Tourette's syndrome, and Parkinson's disease has been discussed in "Nicotinic Acetylcholine Receptors: Molecular Biology, Chemistry, and Pharmacology", Chapter 5 in Annual Reports in Medicinal Chemistry, Volume 30, pp. 41-50, Academic Press Inc., San Diego, Calif. (1995) and in "Neuronal Nicotinic Acetylcholine Receptors," Drug News & Perspectives, Volume 7, pp. 205-223 (1994).
U.S. Pat. No. 5,468,875 discloses N-alkylcarbamic acid 1-azabicyclo[2.2.1]hept-3-yl esters which are centrally active muscarinic agents useful in the treatment of Alzheimer's disease and other disorders.
N-(2-Alkoxyphenyl)carbamic acid 1-azabicyclo[2.2.2]octan-3-yl esters are disclosed in Pharmazie, 48, 465-466 (1993) along with their local anaesthetic activity.
N-Phenylcarbamic acid 1-azabicyclo[2.2.2]octan-3-yl esters substituted at the ortho position on the phenyl ring are described as local anaesthetics in Acta Pharm. Suecica, 7, 239-246 (1970).

Azabicyclic esters of carbamic acids useful in therapy


A magnetic recording medium which has a high areal density and reduced power consumption for recording operations, and a magnetic recording device incorporating the magnetic recording medium. The magnetic recording medium has an upper soft magnetic layer formed uniformly along a plane including the upper surface of a recording layer over the convex and concave portions of a concavo-convex pattern in the recording layer.

1. Field of the Invention
The present invention relates to a magnetic recording medium with a recording layer having a concavo-convex pattern and to a magnetic recording device including the magnetic recording medium.
2. Description of the Related Art
Conventionally, magnetic recording media such as hard discs have been frequently used as recording media for computers or the like. Recently, the magnetic recording media which have a large storage capacity have also received attention as recording media, e.g., for domestic electric appliances, cellular phones, and PDAs (Personal Digital Assistants).
As the magnetic recording media have been widely used, there is an increasing demand for such a magnetic recording medium that requires reduced power consumption for recording operations. In addition, although attempts have been made one after another to improve the areal density of the magnetic recording medium, there is still an increasing demand for further improved areal densities because of requirements for further reduction in size and increase in storage capacity.
Conventionally, the magnetic recording medium has been improved in areal density, e.g., by reducing the size of constituent magnetic particles of the recording layer, refining the materials thereof, and increasing the level of the micro-machining of heads. However, problems such as side-fringes or crosstalk resulting from the limitation of the machining of heads or the spreading of magnetic fields have come to the surface, so that the conventional ways of improving the areal density have reached their limits.
In contrast to this, several magnetic recording media have been suggested as candidates for the magnetic recording medium that can further improve the areal density. The media include discrete track media or patterned media which have the recording layer having a concavo-convex pattern (e.g., see Japanese Patent Laid-Open Publication No. Hei 9-97419).
The recording layer having a concavo-convex pattern makes it easier for a recording magnetic field from a magnetic head to concentrate on the convex portions that are designed to serve as a recording area. This allows for reducing a recording current flowing through the magnetic head for generating the recording magnetic field, thereby reducing power consumption.
Furthermore, the convex portions or recording areas being spaced apart from each other possibly prevent information from being recorded onto adjacent recording areas and cause crosstalk to unlikely occur, thereby allowing for improving the areal density.
However, the demands for further reduction in size of recording devices and recording media and for increase in storage capacity know no limits. Even the discrete track media and the patterned media designed to improve the areal density by patterning the recording layer to have a concavo-convex pattern are also required to provide still further improved areal densities and reduced power consumption for recording operations.

Magnetic recording medium and magnetic recording device


The present disclosure provides embodiments of guard band clipping systems and methods. One guard band clipping system embodiment, among others, includes a vertex processor configured to convert transformed vertex data to integer screen space data and pass the transformed vertex data downstream in a graphics hardware pipeline, and a guard band clipping module coupled to the vertex processor and a guard band arithmetic logic unit coupled to the guard band clipping module, the guard band clipping module configured to determine whether a primitive corresponding to the transformed vertex data is to be clipped and, based on that determination, forward the primitive to the guard band arithmetic logic unit to perform guard band clipping.

Computer graphics is the art and science of generating pictures, images, or other graphical or pictorial information with a computer. Generation of the pictures or images is commonly called rendering. Generally, in three-dimensional (3D) computer graphics, geometry that represents surfaces (or volumes) of objects in a scene is translated into pixels (picture elements), stored in a frame buffer, and then displayed on a display device.
In rendering a picture or image, an object undergoes various processing through various stages of a pipeline while progressing through various coordinate systems, often referred to as spaces. Referring to FIG. 1, the rendering process 10 is shown broadly as progressing from model space 102, to world space 104, to view space 106, to clip space 108, and then to screen space 110. In some implementations, the process may circumvent the world spaces 104 and skip directly from model space 102 to view space 106. Briefly, the model space 102 represents an original coordinate system whereby the particular object to be included in a displayed scene has not been transformed. The model space 102 provides a forum by which the user can manipulate an object on a screen through the use of model transforms. The user may seek to orient or align the object in various manners, shapes, and/or sizes with the help of a user interface to a computer monitor. That is, through a user interface, the user can direct a host processor to perform modifications via various model transforms applied to the object or model, with the result that the model space 102 has evolved to the world space 104.
From the world space 104, further transforms (e.g., view transforms) are applied to the vertices of the transformed object to facilitate projection and clipping, hence evolving into the view space 106. In the view space 106 (also called camera space), various functions take place, such as adding or modifying lighting and/or shading, trivial rejection, and creating a view volume, that enable a determination of what objects can be viewed by the camera and what objects cannot be viewed by the camera. For instance, a view frustum that comprises near and far clipping planes is typically created. Objects of a rendered 3-D scene that do not fit between the near and far clip planes and the sides of the frustum are omitted from processing, hence reducing clipping operations.
In the clip space 108, the coordinates of the frustum created in the view space 106 are normalized (e.g., via a perspective divide) to simplify clipping complexity, and then clipping is performed.
Once the clipping is performed, the primitives within the view volume are mapped to screen space 110 and rendered on a display device. Note that in some implementations, the various aforementioned processes may take place in different and/or additional spaces.
Referring to the clip space 108, various techniques are employed to reduce the number of primitives (e.g., triangles) that need to be clipped. One technique often used is referred to as guard band clipping. In guard band clipping, the near and far clipping planes created in the view space 106 remain unchanged, but the clipping frustum is extended beyond a desired viewport. That is, overall, two frusta are created: a guard band frustum and the smaller viewport frustum. Conditions for rendering and clipping may be implemented according to the following approach. If triangles are located outside the viewport, they are completely discarded. Additionally, triangles are rendered without clipping if within the viewport. Further, clipping is to be implemented if triangles cross both the viewport and guard band frustum or if the triangles cross the near and far clipping planes.
Though guard band clipping offers a conservative approach to rendering (e.g., more triangles may be passed than are needed at rasterization), that conservatism is balanced by a reduction in clipping operations. That is, guard band clipping reduces how often the host processor (e.g., central processing unit or CPU) performs clipping by accepting triangles that are partly off-screen, allowing the host processor to perform simpler and faster culling and clip tests in most cases. Nevertheless, when triangles are to be clipped, the process is arduous and hence time consuming. In conventional systems, clipping is typically performed via execution of one of many different algorithms (e.g., Cohen-Sutherland, Sutherland-Hodgman, Weiler-Atherton, Patrick Gilles Maillot, etc.) on a host processor. Such algorithms often require full sorting (e.g., of view frustum clipping codes), the determination of intersections with view volume clipping planes, and the interpolation of each parameter (e.g., alpha, fog, etc.) of the vertex, which can collectively be a computationally intensive approach that does not map well onto hardware.


A communication system includes a communication device and a relay apparatus that are connected to a network with an external service. The communication device includes a communication unit connected to a browser-installed device and a controller configured to transmit data location information to the browser installed device and output location of the communication device. The relay apparatus includes a communication unit and a controller configured to receive a request, transmit predetermined data based on the request, get the communication-device location information, instruct the browser-installed device to output the communication-device location information, receive authentication data, get the communication-device location information or the correspondence information output by the browser-installed device, and instruct the browser-installed device to transmit the authentication data to the communication device.

There have been proposed an image reading apparatus for uploading an electronic file of a read image to a server. There have been proposed a printer for printing an electronic file downloaded from a server. In order to provide those services, makers of the image reading apparatus and the printer may provide dedicated servers on their own.
Web services capable of storing electronic files in databases prepared on networks by service providers have been in widespread use. For example, a Picasa (a registered trademark) web album and flickr (a registered trademark) are examples of the web services. Users can use communication devices having web browsers to upload or download desired electronic files in the web services.
Thus, the makers of image reading apparatuses or printers may configure the image reading apparatuses and the printers to be capable of direly using those web services, instead of providing the dedicated servers.

Communication system for receiving authentication data from an external service


The invention provides surface-treated metal oxide particles. The surface-treated metal oxide particles have specific ratios of (1) the integrated area of the resonance signals with chemical shifts in the range from −4 ppm to −33 ppm to the integrated area of the resonance signals with chemical shifts in the range from −33 ppm to −76 ppm and (2) the integrated area of the resonance signals with chemical shifts in the range from −76 ppm to −130 ppm to the integrated area of the resonance signals with chemical shifts in the range from −33 ppm to −76 ppm in the CP/MAS 29Si NMR spectrum. The invention further provides a toner composition for electrophotographic image formation comprising toner particles and surface-treated metal oxide particles.

Electrophotographic image formation comprises developing an electrostatic latent image formed on a photoreceptor with a toner comprising a colorant dispersed in a binder resin, transferring the toner image to receiving paper, and fixing the transferred toner image by means of, for example, a hot roll. The photoreceptor is cleaned after the transferring step to prepare for next latent image formation.
Metal oxide particles are often combined with toner particles in order to improve selected properties of the toner particles, including fluidity, transferability, fixability, and cleaning properties. Typically, the metal oxide particles, e.g., silica, alumina, or titania, are subjected to a chemical treatment to render the surface of the metal oxide particles hydrophobic.
In addition, the metal oxide particles strongly influence the chargeability, i.e., tribocharge, of the toner composition. Specifically, toner containing silica as an additive exhibits higher absolute levels of tribocharge than toner containing titania, and toner containing titania exhibits higher absolute levels of tribocharge than toner containing alumina.
However, it is known that the tribocharge of toner containing silica depends on the temperature and relative humidity of the environment. Often, the tribocharging of toner formulated with silica is too high at low humidity and too low at high humidity. As a result, silica produces a large difference in chargeability depending on the environmental conditions, which leads to impaired transferability and ultimately reduced image quality. In contrast, the tribocharging of toner formulated with aluminum oxide is often too low under both high and low humidity conditions. While the chemical treatment to render the surface of the metal oxide particles hydrophobic also affects the tribocharge of toner containing silica and aluminum oxide, the chemical treatment generally fails to overcome the deficiencies of the tribocharge properties of the core metal oxide particle.
Thus, a need exists for toner compositions with improved humidity resistance and/or levels of tribocharge. Specifically, a need exists for chemical treatments of metal oxide particles that allow for control of the tribocharge properties and humidity resistance of the metal oxide particle additives in toner.


The gas sensor control apparatus develops a first voltage based on a first reference voltage at a negative terminal of a gas sensor device through a resistor and a second voltage based on a second reference voltage at a positive terminal of the gas sensor device. A controller samples through the resistor a sensor current, as created upon the development of the first and second voltage for measuring the concentration of gas. When the impedance of the gas sensor device is measured, the controller alternates the first voltage across the first reference voltage. The value (i.e., a zero-point) of the voltage applied to the gas sensor device when the sensor current is zero (i.e., 0 mA) depends upon the first and second reference voltages. The zero-point is corrected by regulating the second reference voltage to match an applying voltage characteristic to the gas sensor device correctly.

1. Technical Field of the Invention
The present invention relates generally to a gas sensor control apparatus which controls an operation of a gas sensor which is equipped with a solid electrolyte layer and works to measure the concentration of gas, and more particularly to such a control apparatus designed to ensure the accuracy of measurement in a gas sensor.
2. Background Art
Limiting current oxygen sensors are used as air-fuel (A/F) ratio sensors designed to measure the concentration of oxygen (O2) contained in exhaust emissions of motor vehicle engines to determine an air-fuel ratio of a mixture charged into the engine. A typical one of such oxygen sensors is equipped with a sensor device made up of a solid electrolyte layer made of, for example, zirconia and a pair of electrodes affixed to the solid electrolyte layer. The measurement of concentration of oxygen is achieved by applying the voltage to the solid electrolyte layer through the electrodes to produce a flow of electrical current through the sensor device as a function of the concentration of oxygen and sampling the electrical current for determining the air-fuel ratio of the mixture.
Ensuring the accuracy of measuring the concentration of oxygen requires control of the voltage to be applied to the sensor device. A variety of techniques are proposed to control the voltage to be applied to the sensor device. For example, Japanese Patent First Publication No. 2004-251891 teaches a gas concentration measuring apparatus which is designed to control the voltage to be applied to the sensor device using an applying voltage characteristic, as defined in the form of a first-order line (will also be referred to as an applying voltage characteristic line below) and to measure the concentration of oxygen in a wide range using an electric current (will also be referred to as a sensor current below) flowing through the sensor device. The gas concentration measuring apparatus also works to change the applying voltage characteristic based on the width of a limiting current range (i.e., a flat range of an output of the sensor device) appearing per given level of the concentration of oxygen within a gas concentration measuring range.
Specifically, the gas concentration measuring apparatus works to change the inclination of the applying voltage characteristic line to bring the voltage to be applied to the sensor device into within the limiting current range (i.e., the flat range) at each of the levels of the concentration of oxygen. The width of the flat ranges of the applying voltage characteristic may, however, be different between sensors. This may not be eliminated only by correcting the inclination of the applying voltage characteristic line. The control of the voltage to be applied to the sensor device has sill left room for improvement.

Gas sensor control apparatus designed to ensure accuracy of measurement in gas sensor


A direct reading prism pole has a tubular housing having an open top, a flange at the open top, a conical bottom portion for wedging the tubular housing into ground soil, a height-adjusting rod partially inserted into the tubular housing by a friction fit, a lip positioned at the top of height-adjustable rod, a laser sensor mounted to the outer surface of the tubular housing for emitting a laser toward the lip to take height measurements of the distance between the laser sensor and the lip, an electronic control unit for receiving the height measurements and providing height reference data, an electronic display for displaying the height reference data, an audio device for emitting an alarm indicating movement of the height-adjusting rod with respect to the tubular housing, and an output device for sending the height reference data to a data collection device.

1. Field of Invention
The invention relates to a prism pole for supporting a reflective prism or other piece of equipment for surveying landforms, structures, etc, which facilitates automatically taking height measurements and providing height reference data corresponding therewith.
2. Description of Related Art
Prism poles as used in surveying to support a reflective prism or other piece of surveying equipment. Prior art prism poles, of the prior art, such as shown in FIG. 1, include a tubular housing and a height-adjustable rod partially inserted therein. The height-adjustable rod slides inwardly and outwardly with respect to the tubular housing. Prior art prism poles include a numerical scale printed on the height-adjustable rod, typically marked in increments of hundredths ( 1/100) of a foot or thousandths ( 1/1000) of a meter. A reflective prism or other piece of surveying equipment attaches to the top of the height-adjustable rod. A prism pole operator can manually read a height measurement from the numerical scale at a point along the height-adjustable rod. The operator typically then records the height measurement into a log book or manually enters the height measurement into a data collection device.
Prior art prism poles allow human error to interfere with accurate measurement-taking. For example, the height-adjustable rod of the prism pole may slowly slip down into the tubular housing, unbeknownst to the prism pole operator. Because the operator is unaware of minor slippage, the operator errs in recording accurate height measurements. Prior art prism poles are also problematic because operators often misread height measurements from the numerical scale. In addition, operators often fail to record changes in height measurements when the operator adjusts the position of the height-adjustable rod. Operators also make transposition errors when manually copying height measurements from the numerical scale into a log book or data collection device. A prism pole is needed that reduces the amount of human error that interferes with accurate measurement-taking.


A method and system for distributing an electronic publication allows the distribution of customized publications, including customized advertising, customized content, or both. In accordance with the method for distributing an electronic publication, an electronic publication is retrieved from storage. The electronic publication is delivered to the consumer by electronically sending the electronic publication to the consumer's electronic mail address.

As the use of the Internet and dial-up computer services have increased, publishers have begun to seek new ways to sell their published works. Various publishers have started creating on-line versions of their magazines that are available through a dial-up service such as America Online. To read one of these on-line magazines, a consumer typically signs on to the dial-up service and reads the magazine while connected to the service.
These on-line magazines, however, have disadvantages. A consumer that is on-line reading an on-line magazine has to pay for the time that he is on-line. These time charges can cause an electronic magazine to exceed the newsstand price of that magazine. Most interactive versions of magazines also do not carry advertisements. Without advertisements, the publisher of the magazine loses a potential source of revenue and advertisers are cut off from consumers. Also, many consumers utilizing dial-up services only have a single phone line, so reading the on-line magazine ties up the consumer's phone line. Accessing on-line magazines may also be inconvenient as a consumer may have to proceed through a number of steps required by the on-line service each time he desires to read the on-line magazine.

Electronic publication distribution method and system

Abstract: In accordance with another aspect of the invention, the electronic publication may include customized advertising. A consumer profile associated with the consumer is stored in a database and comprises a plurality of profile data items. A database of content items and advertising items is created, including at least some targeted advertising items. Each targeted advertising is associated with an inclusion criterion wherein a decision as to whether the inclusion criterion for a particular advertisement has been met depends upon the value of one or more profile data items. The electronic publication is created and comprises some content items and at least one targeted advertising item. The targeted advertising item is included because the inclusion criterion for that targeted advertising item has been met.


Methods and electric vehicle diagnostic systems are provided for diagnosing performance of an active cooling system for cooling a rechargeable energy storage system (RESS) with a coolant. In one embodiment, a method includes determining, via a controller, whether the coolant temperature (TC) is less than the ambient temperature plus a first calibrated value (TA+V1). The method also includes determining, via a controller, whether the coolant temperature (TC) is less than the RESS temperature plus a second calibrated value (TR+V2). When the coolant temperature is less than the ambient temperature plus the first calibrated value and less than the RESS temperature plus the second calibrated value, the method provides for recording a diagnostic pass.

Electric vehicles are rapidly gaining popularity in today's automotive marketplace. Electric vehicles offer several desirable features, such as eliminating emissions and usage of petroleum-based fuels at the consumer level, and potentially lower operating costs. A key component of electric vehicles is the rechargeable energy storage system (RESS), which is typically a battery pack and can represent a substantial proportion of the vehicle's cost. Battery packs in electric vehicles typically consist of numerous interconnected cells, operating at a relatively high voltage, and delivering power on demand. Maximizing battery pack life is a key consideration in the design and operation of electric vehicles.
In order to maximize battery pack life, the temperature in the battery pack must be controlled so that it does not exceed a certain level. Control systems in existing electric vehicles typically prescribe a maximum allowable temperature in the battery pack, and use an onboard thermal management system to prevent battery pack temperature from rising above the prescribed limit. Additionally, the thermal management system may utilize an intrusive diagnostic operation that consumes a large amount of energy and resources to monitor the performance of the thermal management system.
There is an opportunity to employ a non-intrusive active cooling system diagnostic methodology which provides timely analysis by the intrusive diagnostic operation when necessary, but which reduces the diagnostic energy need during typical operation. Such a method could yield cost savings for electric vehicles through the reduction of energy use by the diagnostic mechanisms, and increase customer satisfaction through improved vehicle driving range.
Accordingly, it is desirable to provide electric vehicles with improved methods and systems for diagnosing RESS active cooling systems. In addition, it is desirable to provide non-intrusive methods and systems for diagnosing RESS active cooling systems which use reduced amounts of energy while providing proper diagnostic oversight. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

Methods and systems for diagnosing performance of active cooling system in an electric vehicle


The sense amplifier detects and amplifies a signal read via bit lines from the ferroelectric capacitor of the memory cell. The dummy capacitor provides a reference voltage to bit lines. The dummy capacitor includes a first dummy capacitor and a second dummy capacitor. The first dummy capacitor is provided with a first dummy plate potential at one end to set the reference voltage to a certain potential. The other end is connected to the bit line. The second dummy capacitor is provided with a second dummy plate potential at one end to fine-tune the reference voltage from the certain potential. The other end thereof is connected to the bit line.

1. Field of the Invention
The present invention relates to a semiconductor memory device, and, particularly, to the semiconductor memory device using a ferroelectric capacitor.
2. Description of the Related Art
A ferroelectric memory device (FeRAM) is a semiconductor memory device that may store data in a non-volatilile manner based on two different magnitudes of ferroelectric polarization using hysteresis properties of the ferroelectric capacitor.
Generally, memory cells in the conventional ferroelectric memory employ architecture similar to DRAM. That is, a paraelectric capacitor is replaced with a ferroelectric capacitor, and a ferroelectric capacitor and a select transistor are connected in series to form a memory cell (refer to Japanese Patent Laid-Open No. 2001-250376). Such the memory cells are arranged in a grid to form a memory cell array. On reading data or the like, a word line (a select line) of the memory cell to be read is activated, and a select transistor is made conductive, thereby connecting a memory cell to a bit line.
In addition, a so-called TC parallel unit series-connected type ferroelectric memory is also known. This memory is configured by connecting a cell transistor and a ferroelectric capacitor in parallel to form one memory cell, and such memory cells are connected in series to form a memory cell block (refer to JP 2005-4811A). Both in the DRAM-like structure and in the TC parallel unit series-connected type, two methods can be adopted, respectively. One of the methods is called 2-2 transistor-cell method. This method reads complementary data from two memory cells in the dielectric memory (2T2C method). Another one is called 1-1 transistor-cell method (1T1C method). This method uses a single memory cell, and a comparison and amplification of the signal is made with a reference voltage supplied from a dummy capacitor.
A case where a DRAM-like structure is employed is explained herein as an example.
When the 2T2C method is adopted in the DRAM-like structure, a word line connected to a memory cell to be read, and a word lone connected to a complementary memory cell holding a complementary data are selected. Then, the memory cell and the bit line are connected, and the complementary memory cell and the complementary bit line are connected. Thereafter, the plate line voltage is applied to a plate line, thereby applying a voltage to both ends of a ferroelectric capacitor included in the memory cell and the complementary memory cell. The electric charge from the ferroelectric capacitor of the memory cell is read to a bit line, whereas the electric charge from the ferroelectric capacitor of the complementary memory cell is read to a complementary bit line. Then, the potential of these bit line pair is compared and amplified by a sense amplifier.
On the other hand, in the 1T1C method, a word line connected to a memory cell to be read is selected, and the memory cell and the bit line are connected. Then, the plate voltage is applied to a plate line connected to a memory cell, and the voltage is applied to the both ends of a ferroelectric capacitor included in a memory cell. A reference voltage is thereby supplied to a complementary bit line included in bit line pairs from a dummy capacitor. Electric charge from a ferroelectric capacitor is read to a bit line. The potential of the bit line pairs is compared and amplified by a sense amplifier.
Dummy capacitors are usually used in common for plural memory mats activated at the same time in one memory chip. However, a amount of a signal provided from a memory cell may vary among different memory mats. In this case, it is sometimes difficult, with only one dummy capacitor in a memory cell array, to set an adequate reference voltage while maintaining a preferable margin.


In a packet switch with databases (250, 404) used for packet forwarding, the database pieces are identified by version identifiers (410V) which are used by the packet switch's modules (LCx, RPM0, RPM1) in exchanging information on the databases and requesting updates to the databases. For example, if a primary management module fails and the management is transferred to a secondary management module, the secondary management module requests forwarding modules (e.g. line cards) to identify the database pieces stored on the forwarding modules, and to update the databases as needed. Use of version identifiers reduces the amount of data that has to be transferred in connection with such requests.

The present invention relates to information handling systems (IHSs) that include packet switches. A packet switch can be a network router or other device that receives and forwards data in computer networks based on forwarding databases and possibly based on other information stored on the packet switch. Some embodiments of the invention are useful for managing the forwarding databases and such other information.
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option is an IHS. An IHS generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes. Because technology and information handling needs and requirements may vary between different applications, IHSs may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in IHSS allow for IHSs to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. IHSs may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems, such as a packet switch.
FIG. 1 illustrates an exemplary IP network 104 with routers 110 (i.e. 110.0 through 110.4) and end stations 114, all interconnected by links 120. FIG. 2 is a block diagram of an exemplary router 110. The router includes line cards LCx (LC1 through LCn). Only line card LC1 is shown in detail. The line cards can be identical. Each line card LCx includes a number of ports Px (eight ports in FIG. 1, which are shown as P0 through P7 in line card LC1, and PS through P15 in line card LC2). Links 120 are connected to these ports. Different line cards may contain different types of ports, e.g. optical, electrical, and others, and different line cards may handle different protocols in the same router. If a packet received on one line card LCx must be transmitted on a port of another fine card, the packet is transferred to the other line card by switch fabric 220.
Line cards LCx and switch fabric 220 form the data plane of router 110. The control plane is provided by route processing managers RPM0, RPM1. Each RPM is connected to all the line cards and the switch fabric. Each RPM may have one or more computer processors 224 executing computer instructions 226 stored in memory 228. The RPMs perform managing functions for the switch. For example, the RPMs perform network discovery and provide forwarding databases to the line cards, respond to management requests received over the network or from the switch's own user interface devices (not shown), and perform other management functions. The computer instructions 226 include suitable applications, e.g. IPC 232 (Inter Process Communication) for message exchange between the two RPMs, or between an RPM and a line card LCx or switch fabric 220; and a routing application 234 (e.g. OSPF). Other applications may also be present.
Each incoming packet is processed based on the packet fields. FIG. 3 shows some fields of an exemplary layer-2 packet 310. The packet includes a layer-2 header 314H and layer-2 payload 314P. Assuming for example that the packet arrived at router 110.0 from an end station 114.1, the packet's layer-2 source address 314S may specify the layer-2 address of station 114.1. If the packet destination is station 114.3 for example, then the layer-2 destination address will be the layer-2 address of station 114.3. If the packet destination is another router 110 or a station 114 connected to another router (e.g. station 114.5), the layer-2 destination address will be the layer-2 address of a port Px of router 110.0.
The remaining fields shown are part of the layer-2 payload 314P, which is an IP packet in this example. The IP packet 314P includes IP header 320H which includes a protocol number field 320L indicating the layer-4 protocol, e.g. UDP, TCP, ICMP, etc. The IP header 320H also includes source and destination IP addresses 320S and 320D. If the packet was originated by station 114.1 as in the example above, the source IP address 320S will be the IP address of station 114.1. The IP destination address 320D is the IP address of the packet's final destination, e.g. station 114.3 or 114.5 or a router 110 in the examples above.
In addition to the IP header, IP packet 314P includes IP payload 320P formed according to the protocol number 320L. In this example, the IP payload is a TCP or UDP packet, which includes a header 330H with source and destination ports 330S and 330D. The IP payload also includes layer-4 payload 330P.
Each line card LCx uses its packet processor 236 and memory 240 to determine the port or ports Px on which the packet must be forwarded. Packet processor 236 can be a computer processor which executes instructions stored in memory 240. In addition to the instructions, the memory 240 stores the incoming packets (not shown), and also stores databases 250 used in packet processing. The databases are also stored in each RPM. The RPM versions are shown as 250R0 for RPM0 and 250R1 for RPM1. The line card versions are shown as 250LC. The line card versions can differ from each other and from one or both of the RPM versions due to possible delays in updating each version.
The memory may include different kinds of memory, e.g. CAM (context addressable memory) for some databases, and may include other kinds of memory for packet queues and computer instructions.
Exemplary databases 250 include a layer-2 forwarding table 250.1 ("MAC Table") shown respectively as 250.1LC, 250R.1R0, and 250.1R1 for the line cards and the RPMs. The same suffixes—LC, R0, R1—will be used for the other databases. The databases 250 include also a layer-3 forwarding table 250.2 (routing table, or RIB (Routing Information Base), or its derivative FIB (Forwarding Information Base)), and an ACL 250.3 (Access Control List).
The following table 1 illustrates an exemplary layer-2 forwarding database 250.1 (sometimes called "MAC table" for Media Access Control):
TABLE 1Layer-2 (MAC) lookup table 250.1:Layer-2 destination addressEgress PortsOther Info1267210349824689P15, P643458981578642903P17
The first column contains layer-2 addresses (MAC addresses), and the second column shows egress ports Px for each layer-2 address. If layer-2 destination address 314D of the incoming packet is found in the first column, the packet is forwarded on the port or ports shown in the second column. The second column may alternatively indicate that the packet is to be forwarded based on its layer-3 destination address 320D.
The third column may contain additional information.
The following Table 2 illustrates an exemplary layer-3 forwarding database 250.2 (RIB or FIB):
TABLE 2Routing or Forwarding Information Base 250.2:Destination IP Address prefixEgress PortsOther Info184.108.40.206/15P1, P2, P25 . . .126.96.36.199/15P1, P2, . . .188.8.131.52/31P17
For each entry, the first column includes an IP address and a mask; the mask is the significant number of the most significant bits in the IP address (e.g. 15 bits in the first two entries in the example above, 31 bits in the last entry). This table is searched for the entry with the longest matching prefix, i.e. with the prefix which has the largest number of most significant bits matching the incoming packet's IP destination address 320D. The packet is then forwarded on one or more of the egress ports specified in the second column.
In ACL database 250.3, each entry specifies IP source and/or destination addresses 320S, 320D, and whether a packet with such addresses is permitted or denied forwarding.
Database management involves making changes to databases 250 in response to management messages (possibly in the form of management packets 310 received over the network, or management messages entered from a user interface device (not shown) on router 110). The database changes may result from learning algorithms. For example, each line card LCx learns the association between its ports Px and layer-2 addresses from the incoming traffic: if the line card receives a packet on a port Px, the line card associates the packet's layer-2 source address 314D with the port Px, and enters this association into the line card's MAC Table 250.1LC. The fine card also informs an RPM, and the RPMs inform the other line cards. Also, the RPMs run routing algorithms (e.g. OSPF (Open Shortest Path First), OSPF Incremental SPF, and/or BGP (Border Gateway Protocol), or others) to learn network topology and construct routing tables such as 250.2R0, 250.2R1. This information is then distributed to the line cards. Each line card's database 250.2LC can be identical to the routing tables 250.2R0, 250.2R1, or can be derived from the routing tables (to delete redundant routing paths for example).
In a redundant architecture, one RPM is primary, and the other RPM is secondary. The switch is managed by the primary RPM until the primary RPM fails. The primary RPM's failure may be detected by a line card or the secondary RPM for example. The switch management is then transferred to the secondary RPM in a failover operation. When the switch is managed by the primary RPM, the primary RPM provides copies of its databases 250, and of all the changes to the databases, to the secondary RPM, to avoid the need for database copying during failover. See e.g. U.S. Pat. No. 7,974,315 issued Jul. 5, 2011 to Yan et al., incorporated herein by reference.
Databases 250 may be large, and it is desirable to reduce the amount of communication between the RPMs and between an RPM and the line cards in database management.

Packet switch modules for computer networks with efficient management of databases used in forwarding of network traffic


Disclosed is an electric power supplying unit for use in an electronic apparatus and includes an external AC adapter externally connected to the body of the electronic apparatus for receiving an external AC power source. An internal AC adapter is accommodated into the body of the electronic apparatus for receiving an external AC power source. An AC power source input detection circuit is provided within the internal AC adapter for detecting whether the external AC power source is input to the internal AC adapter. The power supply unit further includes power source switching circuit responsive to the detection output of the AC power source input detection circuit for switching the power supply to the electronic apparatus from the output of the external AC adapter to the output of the internal AC adapter.

1. Field of the Invention
The present invention relates to a power supply unit for use with a portable electronic apparatus and more particularly, a power supply unit and portable electronic apparatus with an AC adapter for converting an AC voltage from an external AC power supply to a DC voltage.
2. Description of Related Art
Currently, there are a variety of personal computers (PC's) available such as desktop, tower and notebook systems. Among them, the notebook PC is designed to be small and light weight in order to provide a portable and transportable use in a mobile environment (i.e., the notebook PC can be used outdoors or at the place it is moved to). A typical example of a notebook PC is an IBM ThinkPad 760 which is sold by IBM Corporation ("ThinkPad" is a trademark of the IBM Corporation).
Almost all notebook PC's are of a battery driven type which can be driven by an internal battery. This is a result of a notebook PC's use in a mobile environment where a commercial electric power source is not available. Conversely, in an office environment where a commercial electric power source is available, an external AC adapter may be attached to a notebook PC to drive the system by a DC input voltage from the AC adapter and charge the internal battery.
It is preferable to use a commercial electric power source which is unlimitedly sustained as a primary power source of a notebook PC rather than an internal battery which has to be cared for its duration or capacity. Consequently, many users that carry a notebook PC also carry an external AC adapter so as to attach it where an AC power source is available. However, while a notebook PC is of a flat shape and a specific form factor (e.g., A4 and B5 sizes) which can be conveniently put into a brief case it is not easy to put an external AC adapter, which is of varying shapes and sizes, into a brief case which is already occupied by the notebook PC. In view of this, a notebook PC of the type which can install an internal AC adapter is recently in advent. An internal AC adapter is an AC adapter which can be contained in the housing of a notebook PC. The internal AC adapter is received in a receptacle space (i.e., media bay) for a detachable storage device such as a CD-ROM drive and a floppy disk drive (FDD).
FIG. 1 schematically shows a powering system of a conventional notebook PC which supports an internal AC adapter.
As shown in FIG. 1, a notebook PC 100 of this type may rely as a primary power source on either a DC output VO of an external AC adapter 10 or a DC output VO' of an internal AC adapter 20. Each output of the AC adapters 10 and 20 is transmitted through output lines 15 and 25 for input in parallel to a DC/DC converter 30. It should be noted that both the external AC adapter 10 and the internal AC adapter 20 are devices for generating a DC output from a commercial electric power source.
The external AC adapter 10 is electrically and detachably connected to the body of the PC 100 by DC inlets 11a and 11b which are provided, for instance, on the wall of the housing of PC 100. The internal AC adapter 20 is exchangeably accommodated, for instance, into the media bay of the PC 100 and is electrically connected to the body of the PC 100 through connectors 21a, 21b. In addition, a power source cable 22 for electrically connecting the internal AC adapter to a commercial power source is detachably plugged in a DC inlet 23 which is exposed on the wall of the housing of PC 100.
The DC/DC converter 30 is a device for converting the DC input to a stabilized DC voltage level which is suitable to drive each hardware element within PC 100 and distribute the output voltage thereof to various portions in PC 100.
The PC 100 is also provided with an internal battery 40 as a primary power source. The battery 40 is usually in the form of a "battery pack" into which a plurality of battery cells are packaged. A re-chargeable battery cell such as Li-ion and NiMH is usually used for the battery cell. The battery 40 is adapted to function as a primary power source of the PC 100 when it is not fed by either one of AC adapters 10 and 20. The AC adapters 10 and 20 are also adapted to charge the battery 40 with their extra electric power. A charge/discharge control circuit 41 controls feeding (charging) the battery 40 as well as feeding (discharging) from the battery 40 to the system.
Incidentally, with an electronic apparatus of the type to which a plurality of AC adapters are attachable, that is, an electronic apparatus having a plurality of AC inputs, a disadvantage exists in that a protecting circuit (e.g., a circuit for protecting from an over voltage or an over current) does not operate properly or the charging current of the battery is excessively large when more than one AC adapter is operated simultaneously. It is therefore necessary to implement in such type of electronic apparatus a mechanism to prevent simultaneous operations of more than one AC adapter or a mechanism for exclusively allowing only one of the AC adapters to supply an output even where a plurality of AC inputs exist.
For example, in FIG. 1, the above disadvantage involved in co-existence of more than one AC adapter can be avoided by providing a switching circuit 50 on the output line 15 of the external AC adapter 10.
The switching circuit 50 is a device for selecting either one of the output VO of the external adapter 10 and the output Vo' of the internal AC adapter 20 and consists of a p-channel MOS FET switch 51 for disconnecting the output line 15 of the external AC adapter 10. The FET switch 51 is serially connected on the output line 15 and has a gate electrode connected to the collector of an npn transistor 53 through a resistor of 20k as an input. The source and the gate electrodes of the FET switch 51 are connected to each other through a resistor of 200k. The npn transistor 53 is provided for connecting/disconnecting the gate electrode of the FET switch 51 to and from ground and has its emitter electrode connected to ground. The emitter and the base electrodes of the transistor 53 are connected to each other through a resistor of 47k. The base electrode of the transistor 53 receives, as an input, the output VO of the external AC adapter 10 (via a resistor of 100k) and the collector electrode of another npn transistor 52 via a resistor of 47k which are ORed together. The transistor 52 is provided for connecting/disconnecting the base electrode of the transistor 53 to and from ground and has its collector electrode connected to the base electrode of the transistor 53 and the emitter connected to ground. The emitter and the base electrodes of the transistor 52 are connected to each other through a resistor of 47k. The base electrode of the transistor 52 receives as an input a detection signal 63 of a detection circuit 60 through a resistor of 47k.
The detection circuit 60 is a device for detecting the DC output VO' of the internal AC adapter 20 and comprises a zener diode 61 connected in parallel to a point P on the output line 25 of the internal AC adapter 20 and a resistor 62 of 20k which connects the other end of the zener diode 61 to ground. The zener diode 61 is an element which has a characteristic in which a reverse current I abruptly increases when a reverse voltage exceeding a zener voltage (Vz: Vz is 5.6 V in FIG. 1) is applied (well known). Therefore, when the output VO' of the internal AC adapter exists, a detection signal 63 is asserted as a result of the reverse current flowing through the zener diode 61. A reverse current blocking diode 70 is inserted in a forward direction in the down stream of the point P on the output line 25 to prevent the detection circuit 60 from being activated by the DC output VO of the external AC adapter 10.
The co-operative operation of the switching circuit 50 and the detection circuit 60 will now be explained hereunder.
It is assumed that the external AC adapter 10 has an AC input while the internal AC adapter 20 has no AC input. In this case, the DC output VO of the external AC adapter is blocked by the diode 70 so that there is no voltage exceeding the zener voltage 5.6 V appearing on the point P on the output line 25. As a result, the output line 63 of the detection circuit 60 is negated and indicates a ground level. The transistor 52 in the switching circuit 50 is switched off due to a low level applied to the base electrode. In response to the transistor 52 being off, the DC output Vo of the external AC adapter in high level is applied to the base electrode of the transistor 53 so that the transistor 53 is switched on. As a result, the FET switch 61 is switched on because its gate electrode is grounded thereby connecting the output line 15 so that the DC output VO of the external AC adapter is supplied to the DC/DC converter 30.
It is next assumed that an AC input is given to the internal AC adapter 20. In this case, the internal AC adapter 20 generates the DC output VO' to apply a voltage exceeding the zener voltage 5.6 V to the point P on the output line 25. As a result, a reverse current I flows through the zener diode 61 to assert the output line 63 of the detection circuit 60. The transistor 52 in the switching circuit 50 is switched on by a high level applied to the base electrode. In response to the transistor 53 being on, the transistor 53 is switched off by ground or low level voltage applied to the base electrode. As a result, FET switch 51 is switched off because the gate electrode is no longer at a low level. With the FET switch 51 being switched off, the output line 15 of the external AC adapter is disconnected and, in place thereof, the DC output VO' of the internal AC adapter 10 is supplied to the DC/DC converter 30.
For example, the IBM ThinkPad 760 series notebook PC (described above) implements a powering system as shown in FIG. 1, which allows an internal AC adapter to be installed. With such a powering system, the AC input is suitably switched depending on the presence or absence of the internal AC adapter so that an erroneous operation of the over voltage/over current protecting circuit of each AC adapter or an excessive powering to the battery is avoided.
It should be noted that a reverse current blocking diode 70 (described above) has to be serially connected to the output line 25 in the feeding system as shown in FIG. 1. It is because, without the diode 70, the output VO of the external AC adapter 10 would flow into the detection circuit 60 so that the detection circuit is unable to exactly detect the presence of the internal AC adapter 20. However, the diode 70 which assumes a significant electric resistance to the current flowing forward is serially connected on the output line 25 for transmitting the main electric power, consuming an electric power of 1.8 W at maximum upon operation of the internal AC adapter 20. Such power consumption is an intolerable waste of electric power and is a heat source within the PC housing. A heat dissipation measure would be required for the heat source, inviting increased consumption of space in the housing as well as an increase in cost.

Electronic apparatus having a power supply unit that can switch between internal and external power sources

International Business Machines Corporation


The invention proposes a tape drive apparatus, tape extraction apparatus and tape cartridge that enable a reliable chucking and chucking release, and a stable carrying of a tape being extracted from a cartridge. The invention is constituted by a magnetically recording/reproducing apparatus; a cartridge mount mechanism 5 whereon a tape cartridge 4 with the magnetic tape T wound therein is mounted; a takeup reel 3 to wind up magnetic T thereon; a leader block 12 attached to one end of the magnetic tape T with a rotation restriction section provided thereon; a chucking mechanism 14 which comprises a chucking pin 27 that restricts the rotation of the leader block and chucks the leader block 12, chucking and releasing chucking of the leader block 12; a carrying mechanism 11 which comprises the carrying section 13 for carrying the chucked leader block 12; a chucking release levers 33 and 34 which releases chucking of the chucking mechanism 14, which is actuated by cams 35 and 36 provided on the carrying section 13 and disposed on both ends of the cam groove 19 for guiding the movement of the leader block 12; and reel motors 53C and 53T including frequency generators 52C and 52T for rotationally driving the tape reel 410 within the tape cartridge 4 and the takeup reel 3, respectively.

The tape drive apparatus that uses a single reel tape cartridge has been in existence. While the existing single reel tape cartridge may be small and convenient for the user to handle or carry it, the cartridge requires, when mounted on the tape drive apparatus, that the tape be extracted from its cartridge and wound onto a takeup reel which is provided within the drive unit.
To meet the requirements, the existing tape drive apparatus comprises a takeup reel having a leader tape within the drive unit. The leader tape comprises a hook at its end. On the other hand, the magnetic tape stored in the tape cartridge comprises a hole to be hooked at its end. When the tape cartridge is mounted on the tape drive to load the tape, the takeup real is actuated, and the end of the leader tape moves through a guide groove provided in the drive unit until the end of the leader tape protrudes from the end of the groove, where the hook at the end of the leader tape vertically faces the hook hole at the end the magnetic tape held immediately above the leader tape. With the hook and hole in this relationship, a hammer provided at the end of the guide groove kicks the end of the leader tape upward, causing the hook hole at the end of the magnetic tape to engage the hook at the end of the leader tape. Subsequently, the takeup reel rotates to wind the leader tape, thereby extracting the magnetic tape from the tape cartridge.
The above-described tape drive apparatus is conventionally constituted such that, the end of the leader tape attached to the takeup reel in the drive unit moves through the guide groove to meet the magnetic tape and hook it to be connected, in order to extract the magnetic tape from the tape cartridge. However, the leader tape, being a flexible resin film, cannot move smoothly and stably to fetch the magnetic tape, and the leader tape also shakes as its hook end vertically faces the hook hole of the end of the magnetic tape, rendering the mutually facing relationship between the hook and hole unstable, and frequently resulting in errors in engaging. On an error in engaging, no second attempt is available, and the tape cartridge must be removed once and remounted at the expense of time and effort.
A human contact or other forms of mechanical shock given to the drive apparatus while carrying the leader tape to the takeup reel may cause the ends of the leader tape and the magnetic tape to unhook from each other.

Tape drive apparatus, tape extraction apparatus and tape cassette


In a substrate for use as a mask blank including a first main surface, a normal region, a frame-shaped region and inner region are present on the first main surface. The frame-shaped region includes first to fourth corner region and first to fourth middle region. The inner region has a flatness of 100 nm or less, the flatness being determined on the basis of a least-squares plane PP1 of the normal region. When one of the corner regions is referred to as an n-th corner region and two middle regions nearest to the n-th corner region are respectively referred to as a first near middle region and a second near middle region, the specific relationship regarding the surface profile is satisfied in the n-th corner region and the first and second near middle regions.

Technical Field
The present invention relates to a substrate for use as a mask blank and to a mask blank.
Background Art
In the field of semiconductor device production, a pattern transfer technology using exposure light and a mask is utilized when forming a pattern on a substrate to be processed, such as a silicon wafer.
In this pattern transfer technology, the pattern of a mask can be transferred to a surface of the substrate to be processed (usually, the surface of a resist) by irradiating the substrate with exposure light through the mask (hereinafter, this process is referred to also as "transfer process"). Thereafter, the resist is developed. As a result, the substrate to be processed can be made to have the resist which has a desired pattern.
In recent years, attention is in particular being focused on an ArF exposure technology in which ArF excimer laser light is used and on an EUV exposure technology in which EUV exposure light is used, in order to render micropattern transfer possible.
For example, EUV (extreme ultraviolet) light, which has wavelengths shorter than ArF excimer laser light, is used for the EUV exposure technology. The term "EUV light" herein means light which includes soft X-rays and vacuum ultraviolet light and which specifically has wavelengths of about 0.2 nm to 100 nm. At present, EUV light having a wavelength of about 13.5 nm is being mainly investigated as exposure light.

This patent is subject to a terminal disclaimer.

Substrate for use as mask blank, and mask blank


A plurality of head tips Ra to Rd' and Pa to Pd' are disposed adjacently to each other in such a manner as to project from a peripheral surface of a rotary drum 2 by a predetermined length and at the same time the projecting lengths of the head tips Ra to Pd' are selected in such a way so that the surface pressures of a plurality of head tips Ra to Pd' on the magnetic tape 9 become uniform. Outer head tips are inclined by a predetermined angle and fixed. With such an arrangement, since the gap positions of the head tips become the center of tape contact against the magnetic tape 9, the surface pressures of the magnetic tape 9 against the head tips become substantially constant. If the surface pressures become constant, the head tips uniformly wear.

1. Field of the Invention
This invention relates to a rotary magnetic head device which is preferably applied to a digital VTR having several rotary magnetic heads (head tips) mounted thereon or the like.
2. Description of the Prior Art
It is well known in the prior art of the digital VTR that as the number of revolutions of the rotary drum is increased to perform a recording/reproducing operation or the number of recording/reproducing heads is increased to process the data in parallel to perform recording/reproducing operation so as to process a large amount of data. In case of a digital VTR in which high definition signals for use in reproducing high definition images are recorded or reproduced, a certain type of digital VTR employs the latter process.
In this type of digital VTR, the data rate to be recorded or reproduced reaches about 1 Gbps, so that eight magnetic heads are used as the rotary magnetic head device for recording/reproducing operation. FIG. 4 illustrates one example of an arrangement of the magnetic heads. In the case that the magnetic heads constructed of a plurality of head tips are fixed onto the rotary drum 2 (actually the rotary plate disposed between the upper and lower divided drums), that the plurality of head tips are equally spaced apart on the rotary drum 2 and disposed on it. However, this arrangement may cause a problem of a crosstalk of signals, so that as shown in FIG. 4, the magnetic heads are concentrically fixed at a part of the drum.
In FIG. 4, reference numerals 3 and 4 denote recording heads in which four head tips (Ra, Rb, Rc, Rd) and (Ra', Rb', Rc', Rd') are disposed adjacent to each other, respectively, and each of the heads may act as an independent recording head. The recording heads 3 and 4 are angularly spaced apart by about 180.degree. . Reference numerals 5 and 6 denote reproducing heads in which each of four head tips (Pa, Pb, Pc, Pd), (Pa', Pb', Pc', Pd') is disposed adjacent to each other in the same manner as that of the recording heads 3 and 4 and each of the heads any act as an independent reproducing head. As shown in the figure, the reproducing heads 5 and 6 are angularly disposed by about 180.degree. at a position shifted by 90.degree. from each of the recording heads 3 and 4.
Four head tips constituting the recording heads 3, 4 and the reproducing heads 5, 6 are formed as small as possible and an inter-head tip distance is made as small as possible to cause the four head tips to be mounted on the same head base (not shown). As described above, an entire mass and a shape of the head base are formed small to facilitate a manufacturing of the head and additionally it has an effect that a centrifugal force acting against the head base can be reduced during its use.
Each of the head tips (Ra, Rb, Rc, Rd), (Ra', Rb', Rc', Rd') and (Pa, Pb, Pc, Pd), (Pa', Pb', Pc', Pd') is fixed so as to be in parallel to each other and at the same time as shown in the figure, they are disposed to show the same length (a projecting amount).
As described above, when the magnetic head tips are used while they are disposed in parallel to each other and have the same projecting length (a projecting amount), the recording heads 3, 4 and the reproducing heads 5, 6 gradually wear. Since this wearing phenomenon is equally found in all the heads, only the recording head 3 will be studied. In this case, the four head tips do not uniformly wear, but the outer two head tips Ra and Rd wear more than the inner two head tips Rb and Rc. This is due to the fact that the outer head tips Ra and Rd have a higher surface pressure (a tape contact pressure) than that of the inner head tips Rb and Rc.
In addition, the outer head tips have a larger tape noise than that of the inner head tips and further it has been confirmed that the tape noise deteriorates as a ratio of S/N.


An electronic device includes a housing, a plurality of microphones, and a plurality of guide tubes. The plurality of microphones are disposed in the housing. The plurality of guide tubes extend from the housing toward the plurality of microphones, whereby the plurality of microphones in the housing receives external sound via the guide tubes.

1. Field of the Invention
The invention relates to a microphone array in a housing receiving sound via guide tubes.
2. Description of the Related Art
A microphone array includes a number of microphones disposed in tandem. A simple example is shown in FIG. 1, wherein the microphone array 10 includes two microphones 11 and 12 placed side by side. Directivity of the microphone array 10 can be achieved by manipulating the signal received by the two microphones 11 and 12. Assuming the two microphones 11 and 12 are omni-directional and having the same characteristics, the directivity of the microphone array 10 depends on vector {right arrow over (d)} from one microphone 11 to the other microphone 12.
The above-mentioned microphones 11 and 12 are conventionally placed in an open space to achieve directivity. Most electronic devices (cellular phones, personal digital assistants, etc.), however, have plastic or metal housings, acting as acoustic isolators which block audio signals, thus increasing the difficulty of microphone placement. Furthermore, the majority of electronic elements including microphones are conventionally surface-mounted on printed circuit boards (PCBs), thus limiting the directivity of the microphone array. As illustrated by FIG. 2, microphones 11′ and 12′ are disposed in a housing 20. The housing 20 acts as an acoustic isolator preventing the microphones 11′ and 12′ from receiving external sound. Furthermore, the distance d1 between the microphones 11′ and 12′ on the PCB 21 is limited by the available space on the PCB 21 and in the housing 20, generally being less than the desired distance (d1<d). Furthermore, the direction of the microphone array, as designated by vector {right arrow over (d1)}, is always parallel to the PCB 21. Such a direction, however, does not necessarily target the desired sound source during operation of the electronic device.

Microphone array in housing receiving sound via guide tube