An anaerobic process in accordance with the present invention includes the step of digesting an organic substrate in a first anaerobic reactor to provide reactor contents comprising solids and liquid products of digestion. The process also includes a step of removing a portion of the reactor contents, and a step of pasteurizing all or part of the removed reactor contents by direct contact with a hot or inhibitory fluid to cause pathogen destruction. The fluid may be in a gaseous or liquid phase and the fluid may have inhibitory effects which causes the organisms to undergo lysis.

The present invention relates to an anaerobic treatment process for digesting organic substrates and producing residual solids containing reduced concentrations of pathogens. More specifically, this invention pertains to a method of pasteurizing sludge to bring the sludge to within exceptional quality as defined by the Environmental Protection Agency while maximizing solids destruction through the pasteurization.
Anaerobic digestion is used to convert a variety of organic materials to gas and soluble constituents. Anaerobic digestion is commonly used to convert a fraction of sewage sludge, animal manure, and other putrid organic slurries containing substantial quantities of pathogenic bacteria, viruses, fungi, and parasites to methane gas and soluble products. Conversion of sewage sludge, or other waste solids to gas and soluble constituents lowers the cost of solids disposal by reducing the mass of solids requiring disposal. Examples of processes that are useful for converting organic materials to gas and soluble constituents include the retained biomass processes described in U.S. Pat. Nos. 5,015,384 and 5,670,047 by the inventor of the subject application. The ""384 patent describes a retained biomass process similar to the one illustrated in FIG. 1. In such a process, an influent slurry 1 is delivered at a rate Q to anaerobic reactor 8. Solids, comprising partially digested solids and anaerobic bacteria, and liquid and soluble products of digestion are delivered via line 2 to a separator 9 where the solids are separated from the liquid and soluble products of digestion. The ""384 patent describes that the solids are either returned to anaerobic reactor 8 or they can be wasted via line 5 for disposal. Effluent from the separator can be discharged via line 4.
Retained biomass systems substantially improve the economics of anaerobic digestion. The digestor size can be significantly reduced while improving the percent solids converted to gas and soluble products. In a retained biomass system, solids must be wasted from the system on a periodic basis to avoid their undesirable build up. Referring to FIG. 1 and 2, solids can be wasted from separator 9 along line 5 or from the thickened return solids stream 3 shown in FIG. 1. Solids can also be wasted from the digestor 8 or from line 2 as shown in FIG. 2. Typically, it is more economical to waste the concentrated solids from the thickened solids stream 3 or directly from the separator 9 shown in FIG. 1, as compared to wasting the less concentrated digestor solids as shown in FIG. 2.
In addition to the volume and mass of residual waste solids, the cost of disposing waste solids is also influenced by the quality of solids requiring disposal. Solids, which have lower concentrations of bacteria and viral pathogens, can be disposed at less cost than solids containing higher concentrations of pathogenic organisms. Current regulations (EPA-40 CFR Part 503) define Class A or xe2x80x9cexceptional qualityxe2x80x9d biosolids as those waste solids containing a reduced quantity of pathogenic bacteria such as salmonella, and fecal coliform. Class A biosolids can be produced through a variety of means including:
1. Disinfection by holding the waste solids (biosolids) at an elevated temperature (above 50xc2x0 C.) for a prolonged period of time. Shorter detention times are achieved at higher temperatures. Pasteurization is achieved by retaining the solids or slurry for 30 minutes or more at 70xc2x0 C. or higher.
2. Raising the pH above 12 for 72 hours at an elevated temperature, or drying to 50% solids concentration.
3. In vessel or aerated composting for three days at 55xc2x0 C.
4. Windrow composting at 55xc2x0 C. for 15 days
5. Heat drying at 80xc2x0 C.
6. Heat treatment of liquid biosolids to 180xc2x0 C. for 30 minutes.
7. Aerobic thermophilic digestion at 55xc2x0 C. for 10 days
8. Beta ray irradiation
9. Gamma ray irradiation
As can be observed from the list above, the waste biosolids must have the pH or the temperature elevated for prolonged periods of time to achieve the desired pathogen reduction. The cost of achieving the desired pathogen reductions according to the above methods is directly related to:
1. The energy or chemical cost required to elevate and maintain the temperature of the waste biosolids; and
2. The reactor size required to hold the waste solids for the required period of time.
The quantity of chemicals used, the energy required, and holding vessel size, are each dependent on the quantity of solids that must be processed to reduce the pathogen concentration.
Specific methods of producing anaerobically digested xe2x80x9cClass Axe2x80x9d biosolids include the following processes:
1. Plug flow anaerobic thermophilic digestion or simulated plug flow digestion through a series of completely mixed thermophilic digesters. In this type of process the entire influent flow is heated to thermophilic temperatures. Heat losses from the digestors can be significant, since the volume to surface area required for multiple digestors is low. High effluent organic acids and ammonia concentrations, and the poor dewaterability of the residual solids are significant disadvantages of anaerobic thermophilic digestion or simulated plug flow digestion.
2. Batch pasteurization of the entire influent flow prior to anaerobic digestion is a commonly used practice. However, pasteurization of the entire influent flow prior to anaerobic digestion is expensive since the entire viscous flow must be pasteurized. The procedure requires large quantities of energy for transporting and heating the viscous influent slurry.
3. Thermophilic anaerobic digestion followed by mesophilic anaerobic digestion (Dague, et al. #5,746,919) has been described as useful to achieve Class A biosolids. However, in order to meet the strict requirements of EPA-40 CFR Part 503, in such a process the thermophilic digestor should operate in a plug flow mode to prevent short-circuiting, i.e., passage of a portion of the biosolids without being exposed to the treatment conditions for a sufficient period of time to effect the desired results. Again, with this type of process, the entire flow of biosolid stream must be heated to thermophilic temperatures and maintained at those temperatures for a considerable period of time, generally exceeding 7 days in the thermophilic reactor and 12 days in the mesophilic digestor. Such long retention times and large volumes contribute significantly to the overall cost of the process. In addition, two biomasses, mesophilic and thermophilic, are grown, thus reducing the mass converted to gas while increasing the mass to be disposed.
4. Thermophilic aerobic digestion followed by mesophilic anaerobic digestion also provides a process to achieve Class A biosolids. However, in order to meet the strict requirements of EPA-40 CFR Part 503, in this process the thermophilic aerobic digestor is generally operated in the plug flow mode or as a sequencing batch reactor to prevent short-circuiting. Again the entire flow must be heated to thermophilic temperatures and maintained at those temperatures for a considerable period of time, generally exceeding 5 days in the aerobic reactor, and 12 days in the anaerobic digestor. Costs associated with the heating, transporting and storing the process stream can be significant. In addition, a significant portion of the methane gas generating potential is lost in the aerobic portion of such process.
5. U.S. Pat. No. 5,888,453 describes a continuous flow pasteurization process for sewage sludge. The process described in the ""453 patent involves raising the temperature of the sludge by passing the sludge through at least one heat exchanger supplied with a heating fluid. The sludge at the elevated temperature is delivered to a detention tank where it is held above a predetermined temperature for a predetermined period of time to effect pasteurization. The ""453 patent describes that the pasteurized sludge can be fed to a second anaerobic reactor for further digestion, followed by delivery to a dewatering system.
There continues to be a need for an energy efficient anaerobic digestion process capable of effectively and efficiently digesting organic substrates and producing residual solids that contain reduced quantities of pathogens so as to be classified as Class A or xe2x80x9cexceptional biosolidsxe2x80x9d by the EPA.
The present invention provides a method for anaerobically digesting organic substrates and producing residual solids that contain pathogens at a level that allows the residual solids to be classified as Class A biosolids. The method concentrates digested products which reduces the volume of material that must be treated to reduce the pathogen levels. Reducing the volume of material that must be treated provides cost savings associated with reduced energy costs and equipment costs. Direct contact with a hot or inhibitory fluid is relied upon to treat the residual solids to reduce the pathogen levels. Preferably, steam is used as a relatively inexpensive source of heat and also provides a source of fluid to dilute the residual solids so that they can be subsequently treated in an additional anaerobic reactor to further reduce the solids volume. Gases such as air, oxygen, nitrogen, hydrogen, methane, and carbon dioxide may also be used as a source of heat either alone or in combination with other gases. Inhibitory gases such as ammonia, hydrogen sulfide, ozone and in some cases oxygen may be used to cause the pathogens to undergo lysis or used as a heat source alone or in combination with other gases.
An anaerobic process in accordance with the present invention includes the step of digesting an organic substrate in a first anaerobic reactor to provide reactor contents comprising solids and liquid products of digestion. The process includes a step of removing a portion of the reactor contents, and a step of pasteurizing all or part of the removed reactor contents by direct contact with a hot or inhibitory fluid.
In a preferred embodiment of an anaerobic process in accordance with the present invention, the process includes the steps of; digesting an organic substrate in a first anaerobic reactor to provide reactor contents comprising solids and liquid products of digestion, removing a portion of the reactor contents, concentrating the portion of the removed reactor contents by separating liquids, returning concentrated reactor contents to the first anaerobic reactor, pasteurizing any leftover concentrated reactor contents by direct contact with a hot or inhibitory fluid, and digesting the leftover reactor contents that underwent pasteurization in a second anaerobic reactor. In the preferred embodiment, the fluid to bring the leftover concentrated reactor contents to the desired temperature may be either in a gaseous or liquid phase or any combination thereof. If the fluid is in a gaseous phase, the gaseous phase may be either steam, air, nitrogen, oxygen, carbon dioxide, hydrogen, hydrogen sulfide, ozone, methane or ammonia or any combination thereof. If the fluid is in a liquid phase, the liquid phase may be water. The fluid may also have disinfectant chemicals.
In another embodiment of the present invention, the anaerobic process includes the steps of; digesting an organic substrate in a first anaerobic reactor to provide reactor contents having solid and liquid products of digestion, removing a portion of the reactor contents, concentrating removed reactor contents by separating liquids, returning concentrated reactor contents to the first anaerobic reactor and pasteurizing any leftover concentrated reactor contents by direct contact with a hot or inhibitory fluid. During pasteurization, gases such as ammonia or hydrogen sulfide may be given off and reintroduced into the process. Since the pasteurized reactor contents and the gases are substantially in equilibrium, reintroducing part or all of the gases contributes to the heat energy required for pasteurization, thus, conserving energy. In addition, the nature of these gases causes the cells to undergo lysis. In this embodiment, the fluid may have a gaseous or a liquid phase or any combination thereof. If the fluid is in a gaseous phase, the gaseous phase may be either steam, air, nitrogen, oxygen, carbon dioxide, hydrogen, hydrogen sulfide, ozone, methane or ammonia or any combination thereof. If the fluid is in a liquid phase, the liquid phase may be water. The fluid may also have disinfectant chemicals.
Using the processes in accordance with the present invention, exceptional quality, xe2x80x9cClass Axe2x80x9d biosolids may be achieved efficiently and economically.

Pasteurizing sludge to exceptional quality

Western Environmental Engineering Company


A method for maximizing the loading capacity of a wagon or wagon train when loading with pourable material from a silo. The method utilizes a computer which determines the type of wagon to be loaded on the basis of values obtained with sensors.

Bulk materials are normally loaded onto railway freight cars or wagons, by passing a number of mutually hitched wagons through a loading zone above which there is arranged a storage unit or silo in which bulk materials, such as ore concentrates or pellets, are stored. The material is discharged from the silo down into an underlying wagon through the medium of a chute provided with an outlet opening, referred to here as a material delivery chute. Loading of the wagons takes place automatically and the outlet end of the delivery chute is provided with a flap whose width is sufficient to cause the material pouring from the chute to be distributed uniformly in the wagon.
Australian Publication B 55576/86 teaches one such type of loading arrangement where the intention is to distribute the weight of the material equally at both ends of the wagon while, at the same time, maintaining an essentially constant height, or level of the material in the wagon, therewith to utilize the capacity of the wagon effectively. To this end, the wagon is weighed and its height is determined and also its passage through specific points. On the basis of this information, the material delivery chute is controlled to deliver a specific volume or weight of material to the wagon and to distribute the material uniformly in the wagon while levelling the material therein at the same time.
When seen against the background of the number of wagons that annually transport bulk materials of the aforesaid kind, such as ore, ore concentrates or pellets, it is a natural aim to utilize the load capacity of each wagon and each wagon train to a maximum. Wagon wheels and wagon baskets become worn and in time a wagon may become one or two tonnes lighter in weight. Its loading capacity has not diminished, however. The endeavour to constantly utilize the full load capacity of individual wagons or freight cars is readily understandable.

Method to maximally utilize the loading capacity of an individual wagon and the train when loading with bulk material


A fruit and vegetable picking method and device based on machine vision and storage medium that includes: acquiring fruit image of fruit or vegetable to be picked currently, calling pre-trained neural network model to identify fruit image, and determining type of fruit or vegetable; acquiring type of fruit or vegetable, and determining cuttable area on stalk of fruit or vegetable according to type of fruit or vegetable, locating cutting point; controlling end picking apparatus to cut off stalk of fruit or vegetable, according to cutting point being determined. By using pre-trained neural network model to detect fruit and cut stalk for picking, one device may be able to pick multiple fruits and vegetables, have high versatility and picking accuracy, avoid hurting pulp, and have improved harvest efficiency and quality of fruits and vegetables picked.

In recent years, developing an intelligent robot is a research hotspot. Through an application of the intelligent robots, it is able to effectively improve an operating efficiency and reduce a labor intensity and a production cost in an industrial and agricultural production. In terms of an agricultural robot, a fruit and vegetable picking robot is one main means of developing a modern agricultural production, while a visual recognition and picking method of a picking robot is one key technology that is able to successfully complete a picking operation. However, comparing to a current development of the agricultural production at home and abroad, a research achievement of the picking robot is rather few. A recognition system of most picking robots can only identify a single type of fruit or vegetable, thus can only be applied to pick a single type of fruit or vegetable, while each type of the fruits requires a different robot arm and a different end picking apparatus, which has greatly increased a processing cost of the picking robot. At a same time, most robots achieve picking through grabbing a pulp. However, for different types of fruits or vegetables, or even a same type of the fruit or vegetable in a different shape or at a different position, a grabbing point and a grabbing moment is different, while a fruit and vegetable picking robot in the prior art is not able to determine a specific grabbing point according to a plurality of factors including a type, a shape, and a position of the fruit or the vegetable, which affects a picking accuracy.
Therefore, the current technology still needs to be improved and developed.

Fruit and vegetable picking method and device based on machine vision and storage medium


The image forming apparatus includes: a first liquid ejection device which, while scanning to and fro in a direction substantially orthogonal to a conveyance direction of a recording medium, ejects a first liquid containing a coloring material onto the recording medium; second liquid ejection devices which are disposed respectively on both regions in a scanning direction outside the first liquid ejection device, the second liquid ejection devices ejecting a second liquid onto at least an area of the recording medium on which the first liquid is to be deposited prior to the first liquid being deposited while the second liquid ejection devices perform a scan together with the first liquid ejection device; and first radiation irradiating devices which are disposed respectively on both regions in the scanning direction outside the first liquid ejection device, the first radiation irradiating devices irradiating an area of the recording medium on which the first liquid and the second liquid have been deposited with a radiation while the first radiation irradiating devices perform a scan together with the first liquid ejection device, wherein at least one of the first liquid and the second liquid contains a radiation-curable polymerizable compound; and at least one of the first liquid and the second liquid contains a polymerization initiator.

1. Field of the Invention
The present invention relates to an image forming apparatus, and in particular, relates to an image forming apparatus that fixes a coloring material-containing ink on a medium through reaction between the ink and a treatment liquid, so as to form a desired image on the medium.
2. Description of the Related Art
In recent years, inkjet recording apparatuses have become widespread as image forming apparatuses for forming images such as pictures and documents on media. An inkjet recording apparatus forms a desired image on a medium by ejecting ink droplets onto the medium from nozzles in heads while moving the heads relatively to the recording medium.
Depending on the type of the medium and the types of the inks, a phenomenon of deposition interference may occur in which an ejected ink droplet overlaps (contacts) at least part of another ink droplet already on the medium, whereby the ink droplets become mixed together. Moreover, if the deposited ink penetrates into the medium, then smearing or spreading out of the dots formed may occur. To prevent image degradation due to such deposition interference and so on, an inkjet recording apparatus has been. proposed according to which ink and a treatment liquid that can react with the ink are deposited onto a medium, and the ink and the treatment liquid are made to react with one another on the medium, whereby deposition interference of the ink, and the like, are prevented (see, for example, Japanese Patent Application Publication No. 8-72234).
Moreover, an inkjet recording apparatus has been proposed in which an ultraviolet radiation-curable ink is used. After the ink has been deposited onto a medium, the ultraviolet radiation-curable ink is irradiated with ultraviolet radiation, whereby the ink is cured and fixed (see, for example, Japanese Patent Application Publication No. 60-132767, and Japanese Patent Application Publication No. 2003-127517).
However, with a system in question two liquids, i.e. an ink and a treatment liquid, are mixed together, as described in Japanese Patent Application Publication No. 8-72234, if the mixing between the two liquids is insufficient or the balance between the two liquids is poor in places, then the curing of the mixture of the two liquids may be insufficient, and hence there is a possibility that the ink is not fixed on the medium.
Moreover, with a system in which an ultraviolet radiation-curable ink is used, as described in Japanese Patent Application Publication No. 60-132767 or Japanese Patent Application Publication No. 2003-127517, there is a possibility that deposition interference of the ink, or the like, may occur before the irradiation of the ultraviolet radiation is carried out, resulting in degradation of the image quality.


A low leakage Schottky diode and fabrication method thereof. The Schottky diode includes a n-type semiconductor; an anode having a circular periphery formed in a region above the n-type semiconductor; and a cathode formed in a region above the n-type semiconductor and having a pattern surrounding and set apart from the outer periphery of the anode. Because there are no edges at the anode and cathode interface, leakage current is minimized.

1. Field of the Invention
The present invention relates to a Schottky diode and fabrication method thereof. More particularly, the present invention relates to a Schottky diode having a low leakage current and method of fabricating the Schottky diode.
2. Description of the Related Art
A Schottky diode makes use of rectification which occurs at a contact surface between a metal and a semiconductor. The Schottky diode exhibits excellent characteristics, and has been widely used in systems operating at a high frequency, such as a Radio Frequency IDentification (RFID) system.
FIG. 1 illustrates a Schottky diode. In FIG. 1, the Schottky diode includes an anode/anode electrode 10, a cathode/cathode electrode 20, and an n-type semiconductor 30 that are connected to one another.
The anode/anode electrode 10 and the n-type semiconductor 30 form a Schottky contact, and a Schottky barrier is present therebetween. Hence, current can flow from the anode/anode electrode 10 toward the n-type semiconductor 30. Meanwhile, the cathode/cathode electrode 20 and the n-type semiconductor 30 form an ohmic contact.
Referring to FIG. 1, when a forward voltage is applied to the Schottky diode, a current I flows in a direction indicated by the arrow.
FIG. 2 is a plane view of a Schottky diode. Referring to FIG. 2, the Schottky diode is configured with an anode/anode electrode 40 and a cathode/cathode electrode 50 disposed over an n-well 60 defined on a p-type substrate 70, in a pattern as shown in FIG. 2.
As noted, a number of edges or corners are formed at the anode/anode electrode 40 and the cathode/cathode electrode 50, some of which are marked by ◯.
Such edges can cause a leakage current which degrades performance of the Schottky diode. Thus, there is a need to overcome this shortcoming of a conventional Schottky diode.

Schottky diode with low leakage current and fabrication method thereof


A self-locking universal trailer hitch comprising a hitch receiver, a bar and a second receiver, wherein the hitch receiver is secured to a towing vehicle, and wherein the bar is removably secured to the hitch receiver, and wherein the second receiver comprises a locking mechanism to removably secure the second receiver to the bar. The self-locking universal trailer hitch is utilized by securing a trailer to a towing vehicle by obtaining a towing vehicle with a first hitch receiver and a universal trailer hitch with a second hitch receiver, a bar and a second receiver having a locking mechanism, inserting the bar into the pivoting second hitch receiver, locking the bar to the second hitch receiver, inserting the bar into the second receiver and locking the bar to the second receiver via the locking mechanism.

1. Technical Field of the Invention
The preferred embodiment relates generally to a self-locking, universal trailer hitch and method of use, and more specifically to a universal trailer hitch comprising a removable bar that replaces a standard hitch ball and a receiving device for the bar that can alternately be directly secured to a trailer or which can utilize an adapter for securing to an existing hitch on a trailer.
2. Description of Related Art
The most common hitch employed for securing a trailer to a towing vehicle utilizes a trailer ball mounted on the rear of a towing vehicle releasably coupled to a trailer ball socket housing typically mounted on the trailer tongue. When the trailer is small and of light weight, the job of coupling the trailer to the towing vehicle is easily accomplished simply by moving the trailer to the vehicle. However, when a trailer is itself extremely heavy, and particularly when it is carrying a heavy load, such as a heavy boat or camper, it is normally not practical to attempt to pull the trailer to the towing vehicle for the purposes of coupling the trailer to the vehicle. Therefore, with heavy trailer equipment, the common practice is to support the tongue with an adjustable jack and maneuver the vehicle until the ball and trailer couple are aligned and suitably positioned for engagement.
Unfortunately, maneuvering a tow vehicle is a difficult task and reaching alignment of the tow vehicle hitch ball with the trailer hitch is complex, particularly for those who are inexperienced. Due to the weight of the trailer, such cannot readily be lifted and maneuvered so that its hitch is positioned over the tow vehicle hitch ball to form the coupling operation.
A common practice for aligning a towing vehicle with a detached trailer is for one person to monitor the progress of the vehicle towards the trailer while another person operates the towing vehicle. Another practice has been to attach some type of elevated visible marker to the trailer at the location of the trailer ball to assist the driver of the towing vehicle in aligning the vehicle with the trailer, and, once aligned, the driver alone completes the coupling. Appropriately positioned auxiliary mirrors have also been employed.
While it is possible for the vehicle driver to carry out this process alone, engagement under these circumstances is difficult since the vehicle driver is normally required to alternate his/her progress towards the trailer with getting out of his/her tow vehicle to observe how well aligned his/her tow vehicle is with the trailer. It would therefore be desirable to provide a trailer hitch which would enable the driver of the towing vehicle to bring his/her tow vehicle and the trailer into coupling alignment and also to automatically couple and lock the towing vehicle with the trailer, once so aligned.
Various attempts have been made in the past to provide an automatic trailer hitch. One device teaches an automatic trailer hitch having a mountable receiving unit and a separate shank unit. The funnel-shaped receiving unit is mounted on the rear of a towing vehicle, while the shank unit, which supplies the elongated member, is readily removably attached to the ball socket housing of a trailer. While such a device allows utilization of existing trailer hitches, it offers only limited alignment during the attachment process.
Another previous device teaches a swiveling trailer hitch guide. The guide is designed for mounting onto a vehicle bumper having a hitch ball structure. The trailer tongue is forcibly centered over the top of the hitch ball structure during the attachment process. While this device makes the alignment process easier, such a device does not modify the attachment properties of the standard tongue and ball hitch apparatus.
Other devices provide guide rails to direct the trailer hitch toward and onto an existing hitch ball, and while providing some guidance, do not permit approaching the trailer with a tow vehicle from an angle other than directly aligned.
Therefore, it is readily apparent that there is a need for a self-locking, universal trailer hitch that is easy to utilize during the attachment process, facilitates alignment, optionally allows an angled approach, and may also removably secured to a standard trailer hitch receiver.

Self-locking, universal trailer hitch and method of use thereof


An apparatus relating generally to a substrate is disclosed. In this apparatus, a post extends from the substrate. The post includes a conductor member. An upper portion of the post extends above an upper surface of the substrate. An exterior surface of the post associated with the upper portion is in contact with a dielectric layer. The dielectric layer is disposed on the upper surface of the substrate and adjacent to the post to provide a dielectric collar for the post. An exterior surface of the dielectric collar is in contact with a conductor layer. The conductor layer is disposed adjacent to the dielectric collar to provide a metal collar for the post, where a top surface of each of the conductor member, the dielectric collar and the metal collar have formed thereon a bond structure for interconnection of the metal collar and the conductor member.

Microelectronic assemblies generally include one or more ICs, such as for example one or more packaged dies ("chips") or one or more dies. One or more of such ICs may be mounted on a circuit platform, such as a wafer such as in wafer-level-packaging ("WLP"), printed board ("PB"), a printed wiring board ("PWB"), a printed circuit board ("PCB"), a printed wiring assembly ("PWA"), a printed circuit assembly ("PCA"), a package substrate, an interposer, or a chip carrier. Additionally, one IC may be mounted on another IC. An interposer may be an IC, and an interposer may be a passive or an active IC, where the latter includes one or more active devices, such as transistors for example, and the former does not include any active device. Furthermore, an interposer may be formed like a PWB, namely without any circuit elements such as capacitors, resistors, or active devices. Additionally, an interposer includes at least one through-substrate-via.
An IC may include conductive elements, such as pathways, traces, tracks, vias, contacts, pads such as contact pads and bond pads, plugs, nodes, or terminals for example, that may be used for making electrical interconnections with a circuit platform. These arrangements may facilitate electrical connections used to provide functionality of ICs. An IC may be coupled to a circuit platform by bonding, such as bonding traces or terminals, for example, of such circuit platform to bond pads or exposed ends of pins or posts or the like of an IC. Additionally, a redistribution layer ("RDL") may be part of an IC to facilitate a flip-chip configuration, die stacking, or more convenient or accessible position of bond pads for example.
Conventionally, after an etch back for a backside reveal of through-silicon vias ("TSVs"), a conformal dielectric coating is deposited on the surfaces of the substrate and the revealed TSVs. This is followed by planarization to expose conductor vias of the TSVs and to planarize the backside. After which, a metal layer may be deposited for interconnection with the conductor vias. However, this conventional approach may have yield issues and/or cost issues, which make using it less desirable. Furthermore, this conventional approach may not be suitable for individual interconnections.
Accordingly, it would be desirable and useful to provide for post processing after a backside TSV reveal that improves yield, reduces cost, and/or increases versatility for individual interconnections.

Interconnections for a substrate associated with a backside reveal


A touch sensor is disclosed comprising a display device having a substrate on which substrate at least one display electrode is disposed for the display of a shape on the display device. An interface is coupled to the at least one display electrode for receiving display data to the display device. Moreover is a measuring circuit coupled to the at least one display electrode. Switching means are provided for connecting the interface to the at least one display electrode when the switching means is in a first state of operation and connecting the measuring circuit to the at least one display electrode when the switching means is in a second state of operation.

Electrical equipment from various fields of application, e.g. mobile telephones, personal digital assistants (PDA), and industrial control equipment often use a display device of some sort for providing the operator of the device with information. In simpler applications the display device is a one-way communication link, i.e. the display is used for providing information to the operator but not to receive information the other way back. In order to achieve interaction with the operator, push buttons or keyboards are normally used. If the electrical equipment is small sized, for example as with a PDA, normally no room is left on the device for a keyboard, wherein the manufacturer of the PDA must provide other means for enabling input of data into the device.
As is well known in the art the input means may be in form of a touch sensitive display making it possible to enter data without the need for a separate keyboard. Many different techniques for providing touch sensitive devices have been presented and the most common solution today is to use a separate transparent touch sensitive layer which is placed on top of the display. The touch sensitive layer is normally in form of two flexible superimposed plastic sheets that are separated by a small distance by means of insulating spacers. On the surfaces of the sheets facing towards each other, a matrix-like pattern of electrical conductors are arranged which pattern establishes an electric contact between the sheets at the location where the touch sensitive layer is depressed. A control unit scanning the matrix-like pattern on the plastic sheets may then detect the electric contact between the sheets and determine the coordinates for the depression on the display.
Even though the separate touch sensitive layer makes it possible to enter data into the device without the need for a keyboard, it is not an efficient way of realising a touch sensitive display since the transparency of the touch sensitive layer is not absolute hence making it difficult to view the information presented on the display under certain circumstances. The unsatisfactory transparency of the touch sensitive layer is even more noticeable when the display device is provided with back lighter or front lighter technology for making it possible to view the information on the display under poor lit conditions.
Another approach for providing a touch sensitive display is to provide a display with a sensor arranged under the display rather than on top of the display. The sensor then has to detect a touch on the display not by means detecting an electric contact between conductors as with the solution disclosed above, but by using capacitive or reflective properties of the display. In the former case, a capacitive coupling through the display to the finger touching the display makes it possible to detect a touch on the display as well as determine the position of the touch. In the latter case light or sound utilizing changes in the reflective properties of the display at the point of contact may be used for detecting a touch on the surface of the display.
Attempts have been made to provide touch sensitivity for displays without the use of separate sensors arranged on top or below the display surface. An approach is to use the display electrodes forming the pixels or the segments of the characters on the display for sensing the touch.
U.S. Pat. No. 5,043,710 discloses a touch sensor comprising a liquid crystal display (LCD), wherein a touch on the display is sensed by detecting changes in the dielectric properties of the display. A mechanical force applied to the LCD perpendicular to a flexible glass substrate over one of the display electrodes gives rise to a temporary disorganisation of the molecules in the liquid crystal thereby changing the dielectric constant of the liquid crystal under the display electrode. Each display electrode of the LCD is connected to an integrator, wherein a change of the dielectric constant of the liquid crystal when the segments of the LCD are in an excited state gives rise to an electric pulse indicating a touch on the LCD. However, the solution according to U.S. Pat. No. 5,043,710 becomes complex due to the large amount of integrators needed for sensing a touch. Moreover, for sensing a touch the front glass plate needs to be flexible making the display less durable. In addition to this, the working life of the display is also decreased due to the repeated compressions of the liquid crystal in the display.
U.S. Pat. No. 4,224,615 discloses a LCD with a flexible front plate, which LCD may be used as a device for receiving data from a human operator. An operator of a device comprising the touch sensitive display touches the flexible front plate of the display, wherein the front plate deflects towards the back substrate thereby increasing the capacitance between the display electrodes residing in the area being depressed. The capacitance measured between the front and back display segment is compared with the capacitance of a reference cell, wherein it is possible to detect a touch even if the affected display segments are actuated, i.e. presenting a shape on the display. As with U.S. Pat. No. 5,043,710 the invention according to U.S. Pat. No. 4,224,615 uses the change in dielectric constant of the liquid crystal being compressed for sensing a touch. The same problems with robustness and life expectancy as with the invention according to U.S. Pat. No. 5,043,710 exist in the solution according to U.S. Pat. No. 4,224,615.
US 2001/0020578 discloses a LCD with touch sensitivity, wherein the sensor arrangement is placed below a surface of the display. The sensors are preferably placed below the display in the regions of the display where no display segments are arranged. Alternatively, the display segments of the display may be used as sensors provided that the front and back segment are short-circuited. When the display electrodes act as touch sensors, no information may be presented on the screen due to the short-circuiting of the display electrodes. A microprocessor is therefore coupled to the display segments for alternating between presentation of information on the display and touch sensitivity.
U.S. Pat. No. 4,910,504 discloses a touch controlled display device, wherein a touch on the display is sensed by measuring the capacitance between different display electrodes on the front substrate. The font substrate may then be rigid protecting the display from deformation. The detector measuring the capacitance between the electrodes is coupled to the feeding pins of the display. A common counter-electrode is arranged on the back substrate in a manner known per se. As will be disclosed below, the counter-electrode will act as a short-circuit between the electrodes on the front substrate thereby deteriorating the accuracy of the touch sensitive display in regard of where on the screen the touch is made. Moreover, numerous stray-capacitances in the needed drive circuitry for the display will interfere with the capacitance measuring circuitry making it hard to determine where and if a touch is made.
DE 19802479 discloses a touch-sensitive display for use in e.g. elevators. The front surface of display element is provided with an electrically conducting layer which is so thin that the display element is visible through the conducting layer. An evaluation circuit is connected to the conducting layer in order to detect a touch on the display. However, by arranging a conductive layer in front of the display element, the visibility of the display element is deteriorated. Moreover, the conductive layer will be exposed to wear from users of the display, which implies that the endurance of the display will be insufficient for many applications.
For manufacturers of display driver circuits it is of most importance that the circuitry used for detecting a touch on the screen is not affecting the behaviour or the life-expectancy of the driver circuitry. Hence a touch sensitive display which behaves like a "normal" display from a drivers point of view is hence wished for.


Provided is a ground fault detecting device 10 having a ground fault detection part 64 which detects a ground fault of an ungrounded circuit 70 based on a ground fault detection signal St_s of a ground fault signal detection circuit 53 when detection signals S_sig are superimposed on a positive side output part PL and a negative side output part ML by an inverting amplifier 25 connected to the positive side output part PL and an inverting amplifier 35 connected to the negative side output part ML, and having a power supply voltage detection part 66 which detects output voltage of a lithium-ion battery 71 based on a first power supply voltage detection signal Vd1_s of a first power supply voltage detection circuit 52.

1. Field of the Invention
The present invention relates to a ground fault detecting device for detecting ground fault of an ungrounded circuit installed in an electric vehicle or the like.
2. Description of the Related Art
In an electric vehicle (battery-powered vehicle, hybrid vehicle, fuel cell vehicle, or the like) including a direct-current power source which outputs high voltage, it is general to arrange the direct-current power source and a circuit connected to the direct-current power source as an ungrounded circuit insulated from a ground potential section of the vehicle body.
There has been conventionally proposed various configurations to detect ground fault in which the insulation of the ungrounded circuit arranged as such in the electric vehicle and the ground potential section of the vehicle body has lowered (a state of a resistance between the ungrounded circuit and the ground potential section of the vehicle is reduced close to 0 Ω) (for example, refer to Patent Document 1: Japanese Patent Application Laid-Open No. H08-226950, Patent Document 2: Japanese Patent No. 2933490, Patent Document 3: Japanese Patent Application Laid-Open No. 2009-150779, Patent Document 4: Japanese Patent No. 3590679).
In the configurations disclosed in the Patent Documents 1 to 3, since it is not able to detect a power supply voltage of the ungrounded circuit, it is necessary to prepare a voltage detector separate from a ground fault detector. Therefore, there is an inconvenience that the size of the ground fault detecting device increases when it is configured to perform ground fault detection and power supply voltage detection.
Furthermore, the configuration disclosed in Patent Document 4 divides the power supply voltage and applies output voltage of a reference power source to an intermediate potential, and detects ground fault based on flow of current from the reference power source to a ground fault resistance. According to this configuration, there is an inconvenience that ground fault cannot be detected since current does not flow when ground fault occurs with the same electric potential as the output voltage of the reference power source.

Ground fault detecting device for an ungrounded circuit


A processor may receive a packet configured to travel in a network. The packet may be configured to travel from a first device to a second device. The processor may analyze the packet. The processor may detect a password with the packet. The processor may determine whether the detected password complies with at least one password policy. The processor may provide a password policy compliance output to a user. The password policy compliance output may indicate to the user whether the detected password complies with the at least one password policy.

The present disclosure relates generally to the field of password policy enforcement, and more specifically to enforcing a password policy using network-based password policy enforcement.
Computing devices utilize passwords to identify and distinguish users and their access or capabilities on a computing device, across a computing network, or applications internal or externally to the computing network. Passwords can help restrict and prevent users from accessing confidential data or accessing programs that they should not be using.

Network based password policy detection and enforcement

International Business Machines Corporation


An air-fuel ratio sensor early activation feedback system and method includes an air-fuel ratio sensor for measuring an air-fuel ratio in an exhaust gas generated by an internal combustion engine and a heater for heating the air-fuel ratio sensor. A controller activates the heater prior to startup of the engine based on prior startup times for the engine.

The present disclosure generally relates to an air-fuel ratio control system for internal combustion engines, and more particularly relates to an air-fuel ratio sensor early activation feedback system and method.
Exhaust gas sensors are often disposed in the exhaust passages of internal combustion engines for detecting an exhaust gas component concentration for the purpose of controlling the operation of the internal combustion engine or monitoring the status of an exhaust gas purifying system. Specifically, an exhaust gas sensor (e.g., a linear air-fuel ratio sensor) can be disposed at a certain location in the exhaust gas passage and has an element sensitive to an exhaust gas component state to be detected, the element being position for contact with the exhaust gas flowing through the exhaust passage. For example, an air-ratio sensor, such as an oxygen concentration sensor or the like, can be disposed as an exhaust gas sensor upstream or downstream of an exhaust gas purifying catalyst disposed in the exhaust passage for the purpose of controlling the air-ratio of the internal combustion engine to maintain the purifying ability of the catalyst. This is done by using the measured air-fuel ratio to adjust the amount of fuel injected into the engine.
Some air-fuel ratio sensors have a built-in heater for heating the active element thereof for increasing the temperature of the element and activating the element to enable the element to perform its essential functions and also removing foreign matter deposited on the element. For example, when the air-fuel ratio sensor is an oxygen concentration sensor or the like, it can have an electric heater for heating the active element thereof. One such exemplary sensor is a hot wire type that needs to be heated before proper operation is possible. After the internal combustion engine has started to operate, the electric heater is energized to increase the temperature of the active element of the oxygen concentration sensor to activate the active element and keep the active element active.
With recent stricter regulation of exhaust gases, there is an increasing demand for starting the feedback control of the air-fuel ratio as early as possible after the start of the engine, and hence it is desired that the oxygen concentration sensor should become activated as early as possible after the start of the engine. Conventionally, to promote activation of the sensor, as discussed above, the sensor is heated by a heater and this heating does not begin until after the engine is started. Of course, the sensor typically cannot be heated to the activation temperature instantly after the start of the engine and heating. Thus, immediately after the start of the engine, the oxygen concentration sensor is not fully activated, and therefore, until the sensor becomes fully activated, exhaust gases from the engine can contain considerable amounts of unburned HC and sulfur components and hence are in an unstable or unpurified condition.

Air-fuel ratio sensor early activation feedback system and method


Bit-stream Huffman coding may be used for data compression to quickly and efficiently compress relatively small and large datasets. A symbol used in data compression may not be a byte or 8 bits. Rather it has any number of bits. For a certain dataset, a symbol has a dynamic number of bits according to the data size. A symbol may have less than 8 bits for a small dataset, or more than 8 bits for a large dataset. For rapid processing, a large dataset may be broken into smaller datasets that are fast encoded in parallel. Accordingly, the Huffman encoding inputs from a bit-stream instead of a conventional byte-stream and outputs a bit-stream. In particular, bit-stream Static and Adaptive Huffman codings are presented with extended algorithms. Hardware implementation with parallel Huffman encoders and decoders is also illustrated for fast network data compression.

Data communication networks may include various routers, switches, bridges, and other network devices, coupled to and configured to pass data to one another. These devices will be referred to herein as "network elements." Data is communicated through the data communication network by passing Protocol Data Units (PDUs), such as Internet Protocol packets, Ethernet Frames, data cells, segments, or other logical associations of bits/bytes of data, between the network elements by utilizing one or more communication links between the network elements. A particular protocol data unit may be handled by multiple network elements and cross multiple communication links as it travels between its source and its destination over the network.
Compression may be used to reduce the amount of data that must be transmitted on a network. One common form of compression is known as Huffman coding. Although Huffman coding is well known in the art, a brief explanation will be provided to facilitate an understanding of the invention. In Huffman coding, a dataset is first assessed to determine the probability of each symbol occurring. For example, as shown in FIG. 1, assume that a dataset includes five different codes, which are represented by the letters A, B, C, D, and E. The first step will be to determine the respective probability of each letter occurring. In this example, it will be assumed that the probability of A occurring is 0.11, B=0.38, C=0.10, D=0.33, and E=0.08. Each of these letters will be assumed to be a symbol. Note, in this example, the sum of the probabilities of the letters equals 1.00.
The Huffman algorithm uses the symbol probabilities to form a Huffman tree 60 as shown in FIG. 1. Specifically, the Huffman code will find the two symbols with the smallest probability and combine them into a new symbol. The new symbol will represent both symbols and have the sum of the probabilities of the two symbols. In this example, symbols E and C have the two lowest probabilities. Thus, a new symbol will be created EC which has a probability of 0.18. This process will be repeated for each symbol (including the newly created symbols such as symbol EC). Thus, for example, once the new symbol EC has been created with a probability of 0.18, the two symbols with the lowest probability will be selected and combined. In this instance, symbol A has probability 0.11 and symbol EC has a probability 0.18. These symbols will be combined to create a new symbol AEC with a probability of 0.29. This process continues combining symbols to form a tree as shown in FIG. 1.
Within the tree, by convention, each time the tree branches the left branch will be assigned a 1, and the right branch will be assigned a 0. The code for a particular symbol is thus the combination of 1s and 0s that is required to traverse the tree to reach the symbol. In the tree of FIG. 1, symbol A has a code "100", symbol B has a code "0"; symbol C has a code "1011"; symbol D has code "11"; and symbol E has code "1010". Each code uniquely defines a particular letter. The symbols can have different code lengths, as well, since a particular bit pattern will terminate uniquely on one leaf of the tree. Accordingly, more frequently used symbols may be encoded using fewer bits to thus reduce the size of the data that must be transmitted.
To optimize encoding of a particular dataset, the transmitter will scan the dataset to determine the relative probabilities of the symbols occurring in the dataset. This allows the optimum tree to be created for that dataset so that the compression algorithm compresses the dataset in an optimal fashion. To enable the dataset to be decoded, the transmitter transmits a dictionary describing the codes used for the symbols included in the dataset along with the compressed data. The dictionary describes the symbols and probabilities so that the decoder can form a Huffman tree to decode the data contained in the payload. By transmitting a dictionary that is specific to the dataset, the payload may be encoded optimally. The receiver uses the dictionary to build the Huffman tree, and then can use the tree to decode the compressed data. This is commonly referred to as a static Huffman compression process.
Another way that Huffman coding may be implemented is to have the Huffman tree created without transmission of the dictionary. This process requires the encoder to transmit a specific code commonly referred to as a Not Yet Transmitted (NYT) code. When a decoder sees a NYT code, it recognizes that a new symbol is being transmitted to be added to its Huffman tree. In this way the encoder and decoder may build Huffman trees as symbols are encountered. The inclusion of NYT codes in the encoded output, like inclusion of a dictionary, contributes overhead to the compression process. This is commonly referred to as an adaptive Huffman compression process.
Huffman coding works generally for large datasets because, as the size of the dataset increases, the amount of overhead associated with the dictionary becomes comparatively low. Unfortunately, for small datasets, the overhead associated with the compression dictionary may outweigh the benefits obtained from compression, because the combined size of the compressed dataset plus dictionary may be larger than the original size of the uncompressed dataset.
Thus, Huffman coding compresses better with larger sized datasets. However, as the size of the dataset increases, the processing time required to process the dataset also increases. In communication systems and networks, a longer processing time means longer network delay. For example, as described above, since the static Huffman process is required to first scan the dataset to determine the relative probability of each symbol occurring, increasing the size of the dataset increases the amount of data that must be scanned and also results in a more optimized Huffman tree. Although there are adaptive Huffman encoding methods that may eliminate the initial scanning step and allow the Huffman tree to be built over time, as the dataset increases in size, the overall amount of time it takes to rebuild the Huffman tree for each symbol may slow the compression process. In either instance, where it is desirable to encode data in real time, such as where the encoding process is to be used on time sensitive network traffic or other time sensitive data transfers, reducing the Huffman coding time may be equally as important as compressing network data.
As noted above, communication networks generally include network elements that transmit protocol data units between each other. The protocol data units may vary in size depending on the particular types of protocols being used by the network elements to exchange data. A normal Ethernet frame may have a data size from 46 to 1500 bytes. A jumbo Ethernet frame may have a big data size such as 9000 bytes. An IP packet may carry a TCP segment up to 64 KB, but it is not uncommon for IP packets to be on the order of 250 bytes.
Unfortunately, because of the overhead associated with Huffman coding, Huffman coding often does not work well for compression of small sized network packets. For example, assume that an IP packet has a fixed symbol size of one byte (8 bits). Thus, the packet has potentially 256 symbols. If every symbol occurs at least once, the dictionary size will be 256+bytes. If the IP packet is 1024 bytes long, the impact of the dictionary on the overall compressed packet is 25% (256/1024). Assuming an MTU of 1500 bytes, the dictionary impact on the largest size packet will be 256/1500 or approximately 17%. Depending on the compressibility of the data, this overhead may significantly reduce the effectiveness of the compression process, possibly rendering the overall length of the compressed data larger than the original length of the data.
Additionally, for larger datasets, such as Transmission Control Protocol (TCP) protocol data units and other types of larger protocol data units such as jumbo frames using traditional Huffman coding may require significant processing time on a dedicated processor. While delays of this nature may be tolerable in certain instances, in other instances where the transmission is time sensitive the delay associated with compression using standard Huffman coding may prevent the dataset from being compressed for transmission across the network. Accordingly, although it would be advantageous to compress data for transmission on the network, conventional Huffman coding often is not suitable for compressing small datasets due to excessive overhead, or for compressing large datasets because of the relatively large amount of processing time required to compress the large datasets using the standard Huffman coding process.

Bit-stream huffman coding for data compression


The present invention provides an exercise apparatus which utilizes gravity to create a gentle tension upon the lower back. This gentle tension is used in combination with stretching and toning exercises to strengthen and rehabilitate the lower back. The present invention further provides an attached vibratory device attached to the exercise apparatus. The attached vibratory device is used in conjunction with lower back exercises and stimulates the muscle tissue and blood circulation. The apparatus of the present invention comprise the primary structures: a body support structure, a leg support structure and a base connected to both the body support structure and the leg support structure. The apparatus of the present invention further provides for a multitude of different positions in which the therapeutic stretches and exercises may be performed.

A common complaint among individuals is lower back pain. Frequently, the pain results from poor lower back muscle tone or reduced blood circulation to the afflicted area of the body. Vibratory massage is one method currently used to alleviate lower back pain. Typically, a device for creating a vibratory sensation is placed inside of a chair or a cushion. The user then sits upon the chair or leans upon the cushion and turns on the vibratory device. For examples of such vibratory therapy devices see U.S. Pat. No.'s: 2,715,901; 3,678,923; 3,948,379; 4,006,739; 4,971,040 and 5,022,384. For the most part, vibratory therapy devices have been used as passive therapy systems.
More proactive back therapy systems have been devised and are found in the prior art. These devices fall in two classifications: first, systems which utilizes kinesthetics to reduce lower back pain; and second, systems in which the user actively stretches and exercises muscles, thus strengthening and improving muscle tone.
In the first classification, kinesthetic treatment, the proactive therapy system places the user into a work position which reduces any stress and strain upon the lower back. Kinesthetic devices are designed to be used during a workers normal work routine. They serve to reduce problems causing lower back pain and not treat and/or strengthen the muscles of the lower back. An example of a kinesthetic device is found in U.S. Pat. No. 5,487,590 by Haynes.
In the second classification, active exercising devices, body movement is coupled with body placement to perform muscle stretching and exercising. A first example of a back exercise apparatus is found in U.S. Pat. No. 5,070,863 by McArthur et al. which provides an exercise device with two separate rotation axes for back therapy. There is a first vertical axis, generally aligned with the users spine, about which the user twists and turns, and there is a second horizontal axis, perpendicular to the first axis, about which the user can perform back flexion and extension exercises. This device utilizes well known exercises to provide therapy for lower back pain.
A second example of a back therapy system is found in U.S. Pat. No. 5,217,487 by Engle et al. which provides a back therapy device which utilizes a pivotable pelvic support. The user lies on the pelvic support, either face-down or face-up, and performs stretches and exercises. The pelvic support is positioned primarily under the user's center of gravity. However, this device provides a foot rest that is used to stabilize the user when he displaces his center of gravity slightly.
There is a third example of a back therapy system, found in U.S. Pat. No. 5,496,247, by Anderson, which provides a bench type apparatus with a plurality of belts used to anchor the lower portion of the body into place. Once the lower body is anchored into place the lower back muscles are isolated and may be more efficiently exercised.
While the above examples of back therapy devices are useful, none of the known prior art teaches, nor suggests, a device which incorporates both the features and benefits of a passive vibratory system with the features and benefits of an active, exercise oriented, system. Nor does the above prior art provide a device which utilizes gravity to create a gentle tension on the lower back for improved stretching and exercise.


In a rotating machine, a plurality of laminated electromagnetic steel sheets constitutes at least one of a stator and a rotor and a plurality of permanent joining portions to unit each of the laminated electromagnetic steel sheets to form a corresponding one of the stator and the rotor, the plurality of permanent joining portions being set to be located at positions at which an integration value of a magnetic flux density with respect to a plane enclosed with the permanent joining portions is always zeroed.

1. Field of the Invention
The present invention relates to a technical field of a rotating machine applicable to a hybrid vehicle.
2. Description of the Related Art
A Japanese Patent Application First Publication No. 2002-369424 published on Dec. 20, 2002 exemplifies a previously proposed permanent magnet (type) motor that is equipped with a stator on which windings are wound and a rotor constituted by a plurality of permanent magnets and an iron core. A plurality of permanent magnets are arranged in such a way that their respective magnet surfaces are directed toward a radial direction of the rotor with a revolutional axis of the rotor as a center. The iron core is formed of laminated flat rolled electromagnetic steel sheets (or hereinafter simply referred to as laminated electromagnetic steel sheets). The iron core is welded on a peripheral surface of the iron core at a position in a radial direction of the rotor with respect to a magnetic pole center of each permanent magnet.


A method for fabricating a dual actuator assembly for a disc drive. The dual actuator assembly has first and second rotatable actuator assemblies which are axially aligned for independent rotation about a common axis and support at least first and second read/write heads, respectively. The method comprises providing a dual bearing cartridge assembly with a stationary shaft aligned along the common axis having first and second ends, a first rotatable sleeve mounted for rotation about the stationary shaft toward the first end, a second rotatable sleeve mounted for rotation about the stationary shaft toward the second end, and first and second bearing assemblies supporting the first and second rotatable sleeves, respectively. A support member is inserted between the first and second rotatable sleeves to provide a bearing support force in oppostion to the preload force of the first and second bearing assemblies, allowing attachment of the first and second actuator assemblies to the first and second rotatable sleeves, respectively while preventing damage to the bearing assemblies.

A disc drive is a digital data storage device which enables a user of a computer system to store and retrieve large amounts of data in a fast and efficient manner. Disc drives of the present generation have data storage capacities in excess of several gigabytes (GB) and can transfer data at sustained rates of several megabytes (MB) per second.
A typical disc drive is provided with a plurality of magnetic recording discs which are mounted to a rotatable hub of a spindle motor for rotation at a constant, high speed. An array of read/write heads is disposed adjacent surfaces of the discs to transfer data between the discs and a host computer. The heads are radially positioned over the discs by a rotary actuator assembly and a closed loop, digital servo system, and are caused to fly proximate the surfaces of the discs upon air bearings established by air currents set up by the high speed rotation of the discs.
A plurality of nominally concentric tracks are defined on each disc surface, with disc drives of the present generation having track densities in excess of 4,000 tracks per centimeter (10,000 tracks per inch). A preamp and driver circuit generates write currents that are used by the head to selectively magnetize the tracks during a data write operation and amplify read signals detected by the head during a data read operation. A read/write channel and interface circuit are operably connected to the preamp and driver circuit to transfer the data between the discs and the host computer.
The servo system operates in two primary modes: seeking and track following. During a seek, a selected head is moved from an initial track to a destination track on the corresponding disc surface using a velocity-control approach. The servo system initially determines a velocity profile indicative of the velocity trajectory the head should take based upon the length of the seek (in terms of tracks to go to the destination track). The servo system next applies current to an actuator coil to first accelerate and then decelerate the head toward the destination track in accordance with the velocity profile.
During the seek, the servo system sequentially measures (estimates) the actual velocity of the head and adjusts the current in relation to velocity error (i.e., the difference between the actual velocity and the target velocity as set forth by the velocity profile). As the head approaches the destination track, the servo system initiates a settle mode to bring the head to rest over the destination track within a selected settle threshold as a percentage of the track width, such as .+-.10% of track center. Thereafter, the servo system enters the track following mode wherein the head is nominally maintained over the center of the destination track until the next seek is performed.
As will be recognized, a disc drive is primarily utilized to transfer data between the tracks of the discs and the host computer. Such data transfer operations usually cannot occur during a seek, but rather require the drive to be in track following mode. Hence, to maximize disc drive data transfer rate capabilities, high performance disc drives are designed to achieve minimum average seek times. Typical drives of the present generation have nominal seek times on the order of eight milliseconds (msec), facilitating minimum sustained data transfer rates on the order of 20 MB/sec. It will be recognized that achieving a high as practicable minimum sustained data transfer rate is particularly important in sustaining data transfer operations, such as audio-video (AV) and communications applications.
In an effort to increase data transfer performance, designers of disc drives have in the past proposed various approaches which have met with greater or lesser amounts of commercial success. One particularly useful advancement in the art is zone based recording (ZBR) such as exemplified by U.S. Pat. No. 4,799,112 issued Jan. 17, 1989 to Bremmer et al., assigned to the assignee of the present invention. As will be recognized by those skilled in the art, ZBR generally entails defining a plurality of essentially constant bit-density zones across the radii of the discs, so that all of the tracks in each zone have the same number of data blocks (sectors) in which user data are stored. Thus, the number of data blocks per track increases in a step-wise fashion from the inner diameter (ID) to the outer diameter (OD) of the discs. The use of ZBR results in a disc drive transfer rate that varies with radius, with the transfer rate about doubling for tracks at the OD as compared to tracks at the ID.
Another advancement in the art is the use of multiple heads to access the same data surfaces on the discs. As exemplified by U.S. Pat. No. 5,218,496 issued Jun. 8, 1993 to Kaczeus, a head actuator structure is provided having pairs of heads which are angularly offset around each of the corresponding disc surfaces. U.S. Pat. No. 5,343,345 issued Aug. 30, 1994 to Gilovich also proposes a pair of read heads per disc surface, including both single actuator and dual actuator arrangements, with the dual actuators arranged on opposite sides of the disc stack.
Yet another advancement in the art is the use of a plurality of drives in a multi-drive array, sometimes referred to as a RAID ("Redundant Array of Inexpensive Discs"; also "Redundant Array of Independent Discs"). The array operates substantially as a single, large disc drive device. The primary impetus behind the development of such multi-drive arrays is the disparity between central processing unit (CPU) speeds which continue to increase at a phenomenal rate bounded primarily by electronic constraints, and disc drive input/output (I/O) speeds which are bounded largely by mechanical constraints. As will be recognized, an array of smaller, inexpensive drives functioning as a single storage device has been usually found to provide improved operational performance over a single, expensive drive. A seminal article proposing various RAID architectures was published in 1987 by Patterson et al., entitled "A Case for Redundant Arrays of Inexpensive Discs (RAID)", Report No. UCB/CSD 87/391, Dec. 1987, Computer Science Division (EECS), University of California, Berkeley, Calif.
RAID architectures are presently identified by numerical levels of organization, with each level providing different data integrity and I/O throughput characteristics. The particular level (or levels) used in a given application largely depend upon the requirements of the application, with commonly utilized RAID levels ranging from RAID 0 to RAID 7. However, a generally common characteristic of all RAIDs is that data transfer characteristics are enhanced over that of a single disc drive through striping data (i.e., storing portions of the data) across multiple drives in the array.
While these and other well known advancements in the art have allowed system designers to facilitate ever greater levels of disc drive data transfer performance, there remains a continual need for further improvements which enhance the minimum data transfer rate achievable by a disc drive. It is to this and other related ends that the present invention is directed.

Dual disc drive actuator assembly fabrication


Providing protection of point-in-time application data includes obtaining a plurality of original snapshot copies of an original logical volume containing the application data, causing the original snapshot copies to be tested for data corruption, and restoring data corresponding to one of the original snapshot copies. Application data is accessible by an application prior to completion of the restoration. One of the original snapshot copies may be restored to the original logical volume and/or to a new logical volume different from the original logical volume. Prior to completion of the restoration, particular data may be restored to the original logical volume or to the new logical volume prior to an operation to access the particular data. The original snapshot copies may be provided as virtual devices.

1. Technical Field
This application relates to storage devices, and more particularly to the field of protecting data stored in storage devices.
2. Description of Related Art
Host processor systems may store and retrieve data using storage devices containing a plurality of host interface units (host adapters), disk drives, and disk interface units (disk adapters). Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. No. 5,206,939 to Yanai et al., U.S. Pat. No. 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels of the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical volumes. The logical volumes may or may not correspond to the actual disk drives.
It is possible for a logical volume containing application data to become corrupted, either through faulty operation of the application itself or from another source (e.g., improper operation of an unrelated application running on the same host that accesses the same volume). When the data is corrupted, it may be desirable to restore the data to a prior, uncorrupted, state. In systems where periodic backups are performed, the logical volume may be restored from the most recent backup. However, if the time between backups is relatively long, then the prospect of losing a significant amount of data may be unacceptable. For example, if backups are performed daily for a system that handles financial transactions, then restoring a logical volume using backup data means that up to a day's worth of financial transactions may be lost.
One solution to this problem could be to perform backups more regularly. However, many types of backups require copying all the data for a logical volume. Thus, there is a tradeoff between the amount of storage space needed for backup data and the frequency of backups. Moreover, restoring a logical volume from backup data may require taking an application that uses the logical volume off-line while the restoration is occurring, which may not be practical.
Accordingly, it is desirable to provide a system in which the granularity (frequency) of backups may be increased without significantly increasing the need for backup storage while also allowing for applications to operate and modify data during the restoration process.

Protection of point-in-time application data using snapshot copies of a logical volume


According to the present invention, there is provided a pressure sensor unit (1) having a ring-like pressure sensing element (3), which is formed separately from a spark plug, in the state where a spark plug (100) has been attached a rear end of at least one of an inner cylinder member (6) and an outer cylinder member (5) in the direction of an axis (O) is located between the rear end of the pressure sensing element (3) and the rear end of a insulator (110) of the spark plug (standard section (SS)), while at the rear of the standard section (SS), no component of the pressure sensor unit (1) exists in an area inside the inner circumferential surface of the outer cylinder member (5) or its extended plate (EP).

For the purposes of detection of combustion conditions or knocking, improvement of fuel economy, cleaning of exhaust gas, and so on, in an internal combustion engine, the pressure in a combustion chamber of the internal combustion engine has been heretofore detected by a pressure sensor built in a spark plug. The pressure sensor integrated spark plug used for such purposes will be summarized below. That is, a pressure sensing element constituted by a ring-like piezo ceramic element is fitted, together with a ring-like electrode for extracting an output, from outside into a base end position of an attaching screw portion formed in a metal shell of a spark plug. The pressure sensing element is caught by a collar-like sensor retention portion while the pressure sensing element as a whole is covered with a sensor housing from the outside. An output lead wire from the ring-like electrode is extracted rearward from the sensor housing. When the spark plug is attached to a plug hole of an internal combustion engine at the attaching screw portion, the pressure sensor is pressed onto an opening outer edge portion of the plug hole through the sensor housing. The combustion pressure is transmitted to the pressure sensor through the sensor housing. The pressure sensor outputs a voltage proportional to a detected pressure level through the output lead wire by the piezo-electric effect.
However, in the case of the structure in which the pressure sensing element has been built in the spark plug integrally and inseparably as described above, once the life time of the spark plug is expired, the pressure sensor portion together with the spark plug has to be wastefully exchanged for a new one even if the pressure sensor portion is in a working condition. Therefore, Japanese Patent Laid-Open No. 290853/1994 (FIGS. 7 and 8) discloses a configuration in which a pressure sensor is formed separately from a spark plug so that the pressure sensor can be attached to a newly exchanged spark plug and used continuously.
However, the pressure sensor configured thus has a structure in which a lead wire for extracting a sensor output projects sideways from the pressure sensing element and then led out on the rear end side of the spark plug. In such a structure, the pressure sensor is difficult to apply to recent engines in which space saving has been advanced. For example, in recent automobile gasoline engines, a mechanism in the periphery of a cylinder head to which a spark plug is attached is sophisticated. Particularly, in a structure in which a spark plug is attached to the bottom portion of a deep plug hole formed in a cylinder head, valve-system components and so on crowded around the plug hole bottom where a pressure sensing element is located. Thus, in not a few engines, no allowance is left for projecting the lead wire sideways. In addition, the lead wire extracted rearward occupies a certain space in the plug hole. However, in order to save the space in the engine room, there is a type in which a pencil-like ignition coil is installed in the plug hole. In this case, there may occur a problem that the lead wire becomes an obstacle to the installation of the ignition coil.

Pressure sensor unit having a ring-like pressure sensing element


A process for enriching or improving the optical purity of an asymmetric epoxidation reaction mixture is provided wherein the chiral epoxy alcohol enantiomer present in minor amounts is effectively separated from the predominant chiral epoxy alcohol enantiomer. The minor enantiomer is converted to an epoxy ester by stereoselective transesterification using a carboxylic acid derivative such as an enol ester and a lipase enzyme. The desired major chiral epoxy alcohol enantiomer is then recovered or reacted in situ to form a chiral epoxy alcohol derivative.

This invention relates to the purification of epoxidation reaction mixtures. In particular, the invention pertains to the recovery of a chiral epoxy alcohol or chiral epoxy alcohol derivative having high optical purity. The transition metal catalyzed epoxidation of ethylenically unsaturated substrates using organic hydroperoxides as oxidants is a well known method for the preparation of epoxides. In one variation of this technology, optically active epoxy alcohols are prepared by reacting unsaturated alcohols with organic hydroperoxides in the presence of transition metal catalysts containing chiral ligands. The optically active epoxy alcohol products are of great value as intermediates in the synthesis of compounds having high physiological activity.
However, the recovery of pure epoxy alcohols from crude epoxidation reaction mixtures is complicated by the numerous components typically present in such mixtures. The reaction mixture will normally contain a major amount of a first chiral epoxy alcohol, a minor amount of a second chiral epoxy alcohol which is an enantiomer of the first chiral epoxy alcohol, unreacted organic hydroperoxide, unreacted unsaturated alcohol, transition metal catalyst, the organic alcohol coproduct derived from the reacted hydroperoxide, and solvent. Epoxy alcohols tend to be highly reactive and susceptible to decomposition at elevated temperatures, particularly in the presence of Lewis acids such as the transition metal compounds typically used as catalysts in epoxidation reactions.
Moreover, the methods developed to date for the asymmetric epoxidation of unsaturated substrates are not completely stereoselective. That is, both possible stereoisomers of the epoxy alcohol are generated, yielding a reaction product having an enantiomeric excess less than the maximum theoretically possible. Since the physiological activities of the epoxy alcohol product and its derivatives are generally directly related to optical purity, it is highly desirable to obtain a chiral epoxy alcohol having an enantiomeric excess as close as possible to 100%. Conventional physical methods of separation such as fractional distillation, fractional crystallization, extraction, and the like are normally not particularly effective in separating enantiomers either because the optical isomers have very similar physical properties (e.g., solubility, boiling point, melting point) or because of uneconomical losses during purification. Clearly, there is a need for a practical method whereby a chiral epoxy alcohol having enhanced optical purity may be efficiently recovered from an epoxidation reaction mixture.

Process for producing epoxyalcohols of high optical purity


There is disclosed a ball end mill which has a hemishepherical portion formed at a front end of an end mill body. A pair of tip mounting seats are formed at the hemishepherical portion. A main throw-away tip and a second throw-away tip are secured on the tip mounting seat respectively such that the axial rake angle of the main tip is set at a negative angle and the axial rake angle of the second tip is set at a positive angle. There is also disclosed a second ball end mill. In the second ball end mill, only a main throw-away tip is secured on a tip mounting seat. The axial rake angle of the main tip is set at a negative angle. One or more chip breaker grooves are formed on a rake face of the tip.

The present invention relates to a ball end mill having one or more generally arcuate cutting edges arranged at a forward end of an end mill body. More specifically, the present invention relates to a ball end mill capable of providing sufficient rigidity of the end mill body ensuring the cutting performance of the cutting edges, while controlling the chattering of the end mill body.
A conventional ball end mill having two cutting edges is illustrated in FIGS. 21 and 22. The ball end mill in these figures comprises an end mill body 1 in the form of a circular cylinder. The end mill body 1 has a hemishepherical forward end with which a pair of chip pockets 2 and 3 are formed. A pair of tip mounting seats 4 and 5 are formed at a wall surfaces 2a and 3a of the chip pockets 2 and 3 which face in the cutting (rotational) direction of the end mill body 1. A pair of throw-away tips 6 and 7 (hereinafter referred to as "main tip 6" and "second tip 7") are removably mounted respectively to the tip mounting seats 4 and 5 by respective clamp bolts 15.
The main tip 6 and the second tip 7 are made of cemented carbide and formed in the shape of a plane plate having an uniform thickness. Main cutting edges 10 are formed symmetrically about the center of the main tip 6 at intersections between the rake face 6a and the side faces 6b of the main tip 6.
The main cutting edge 10 consists of an arcuate cutting edge 8 having substantially a 1/4 arc and a linear cutting edge 9 rearwardly extending from a rear end of the arc cutting edge 8. Further, the cutting face 6a is shaped in a convex curved surface on the opposite ends of the rake face 6a. A convex curved portion 8a is formed at a edgeline of each convex curved surface. The second tip 7 has substantially the same structural features as the main tip 6. The second tip 7 is formed with a second cutting edges 13 formed at intersections between the rake face 7a and the side faces 7b of the second tip 6 (refer to FIG. 24). The second cutting edge 13 consists of an arcuate cutting edge 11 having substantially a 1/4 arc and a linear cutting edge 12 rearwardly extending from a rear end of the arc cutting edge 11. The second tip is distinguished from the main tip 6 by planar sections 14 which are formed on the side face of the second tip 7 adjacent the front end of the arcuate cutting edge 11.
As shown in FIGS. 23 through 25, the main tip 6 and second tip 7 are arranged such that the front end of the main cutting edge 10 of the main tip 6 is located at the rotational center P.sub.0 of the end mill when viewed from the front end, and such that the front end of the second cutting edge 13 of the second tip 7 is located at the rear position remote from the rotational center P.sub.0, and both tips 6 and 7 are removably mounted respectively to the end mill body 1 by respective clamp bolts 15. Further, the axial rake angles A of the main cutting edge 10 and the second cutting edge 13 are set at a positive angles. According to this construction, when viewed from the front end, the main cutting edge 10 and sub cutting edge 13 are in the shape of a circular arc drawn about the centers P.sub.1 and P.sub.2 located at the side position of mounting faces 6c and 7c of the tips 6 and 7.
Another example for a conventional end mill, there is known as a single edged ball end mill as illustrated in FIGS. 26 through 29. The ball end mill in these figures has substantially same structural features as the above mentioned ball end mill except for having only a main tip 6. Therefore, the same numerals are put on the same components as the above mentioned ball end mill to avoid repetition of the description.
In such a ball end mill as well, the main tip 6 is arranged such that the front end of the main cutting edge 10 of the main tip 10 is located at the rotational center P.sub.0 of the end mill when viewed from front end, and is removably mounted to the end mill body 1 by the clamp bolt 15. Further, the axial rake angle .gamma..sub.A of the main cutting edge 10 is set at a positive angle. According this construction, as shown in FIG. 29, the main cutting edge 10 is in the shape of a circular arc drawn about the center P.sub.1 located at the side position of the mounting face 6c when viewed from front end. According to the above mentioned ball end mills, in order to set the axial rake angles .gamma..sub.A at a positive angle, the wall surface of the tip pockets 2 and 3 facing toward the cutting direction and bottom faces of the mounting seats 4 and 5 must be formed such that these faces are inclined counter to the cutting direction of the ball end mill. For this reason, the thickness behind the chip pockets 2 and 3 gradually decrease toward the rear end of the end mill. As a result, the rigidity of the end mill body 1 decreases, so the chattering of the end mill body occurs often. This sometimes causes the ball end mill to break at the side of the main cutting edge 10 which bears a high cutting load.
In order to solve the above drawback, it may be suggested to set both axial rake angles .gamma..sub.A of the main cutting edge 10 and sub cutting edge 13 at negative angles so as to increase the thickness of the portion behind the chip pockets 2 and 3. However, in such a ball end mill, the cutting performance of the end mill decreases since the cutting resistance affects to the main cutting edge 10 and second cutting edge 13 increase. This results in various drawbacks such as increase of consumption of electric power and frequency of breakage of cutting edge.


The invention relates to a method, device (24) in a network node of a communication network (N), a computer program and a computer program product for investigating the correctness of a communication aspect of a data flow (DF1) passing through the network, where the data flow is provided in relation to a user terminal (10) connected to the network. The device (24) obtains at least one network generated event data record (EDR1; EDR3) of a first type and a network generated event data record (EDR2; EDR4) of a second type, compares the event data records of the first type with the event data record of the second type, determines the correctness of the communication aspect based on the comparison and sends alarm messages (AMI, AM2) in relation to the communication aspect if the two types of event data records indicate differences in the communication aspect.

In communication networks today user terminals are capable of communicating using many various types of data flows. Users may for instance send and receive data flows in the form of electronic messages, such as MMS, SMS, e-mail and Instant Messaging messages. They may also communicate using data flows that are communication sessions, such as video or voice communication sessions.
When such communication data is passed through a communication network it leaves footprints. There are for instance network access log data records such as routing logs that log how and in what way communication data or data flows are routed through the communication network.
There are also charge log data records that are mainly used for determining how much a user is to be charged for a data flow being passed through the network in relation to his or her user terminal.
In relation to this there may be discrepancies. Charge log data records may relate to communication aspects that are wrong, like indicate the wrong types of data flows or have other errors that are not readily identifiable. Also access logs may be erroneous.
Such faults have to be corrected in order for the network to function properly and ensure that it is dimensioned for the right amounts of traffic, but also in order to charge a user correctly for his or her use of the communication network.
The present invention is therefore directed towards improving on this situation.

Investigating a communication aspect of a data flow


There is described an amplifier for a radio frequency signal for transmitting a transmit signal to an otological apparatus. The amplifier comprises at least one power transistor for switching an output signal. A breaker gap of the power transistor is actively connected to a network such that a power loss converted in the power transistor is at least partially reduced during a switchover into a switched-on state and/or at least during a switchover into a switched-off state. The breaker gap of the at least one transistor is at least indirectly connected in series to a power supply source by way of a choke coil. The amplifier comprises a transmit coil as an output load, with the transmit coil comprising an inductor and being actively connected to the power transistor. The transmit coil is coupled to the choke coil in a transformer-like manner, with the choke coil thus being able to transmit an output power to the transmit coil. The transmit coil can generate a transmit signal from the output power.

In the case of a transmit/receive system, data can be transmitted inductively to communicate between an otological apparatus and an accessory for an otological apparatus, for instance a remote controller or a programming device.
In this case, a transmitter has the task of converting supplied electrical energy into energy of a magnetic alternating field in as efficient a manner as possible. Such a transmit signal is subject to the further requirement for a bandwidth which enables data to be transmitted at a predetermined data rate.
In the case of digital transmit/receive systems, which operate with complex modulation methods, with a PSK method, a BPSK method or a QPSK method for instance (PSK=Phase Key Shifting, BPSK—Binary Phase Key Shifting, QPSK—Quad Phase Key Shifting), such a transmitter of a transmit system is subject to the further requirement that a fast phase change is possible. In linear systems, a time which is required for a phase change, is inversely proportional to a bandwidth of a transmit system.
U.S. Pat. No. 6,861,811 B2 discloses a circuit for lighting electrodeless gas discharge lamps. The circuit comprises a half bridge rectifier having two switching elements which each comprise an emitter electrode and a control electrode. The afore-described switching elements can be switched alternately by means of a resonance control circuit. The resonance control circuit is connected to a class E driver, with the class E driver being coupled on the output side to gate terminals of the two switching elements in a transformer-like manner.

Amplifier for a radio frequency transmitter for transmitting a transmit signal to an otological apparatus


In formation of a quantum dot structure in a light emitting layer, a matrix region (an n-type conductive layer and matrix layers) is formed on a growth underlying layer of AlN whose abundance ratio of Al is higher (or whose lattice constant is smaller) than that in the matrix region by an MBE technique, thereby to realize conditions where compression stress is caused in an in-plane direction perpendicular to the direction of growth of the matrix region, and then to form island crystals by self-organization in the presence of this compression stress. The compression stress inhibits an increase in lattice constant caused by the reduced abundance ratio of Al in the matrix region, i.e., to compensate for a difference in lattice constant between the island crystals and the matrix region. The compression stress functions to enlarge compositional limits for formation of the island crystals by self-organization to the Ga-rich side.

Light emitting elements (light emitting devices) including group III nitrides and having quantum dot structures in light emitting layers are well known (see for example Japanese Patent Application Laid-open No. 2002-368267). Those devices achieve highly efficient emission by dispersing, in a matrix region, island crystals which are so minute as to cause quantum effects and which are doped with a predetermined rare-earth or transition-metal element, and then by using the resultant carrier confinement effect of quantum dots.
The formation of conventional quantum dot structures as disclosed in Japanese Patent Application Laid-Open No. 2002-368267 is done using so-called self-organizing techniques. Those are techniques for achieving quantum dot structures in epitaxial growth processes using well-known growth techniques such as MBE, by constituting the island crystals using a substance which has some difference in lattice constant from the one constituting the matrix region as well as by appropriately controlling the composition, the substrate temperature, the atmosphere, and the like. Those techniques allow easy formation of island crystals which act well as quantum dots, without requiring artificial and direct shape control such as micromachining.
It has been shown that no cracks are generated if a so-called AlN template substrate including an AlN film epitaxially formed on a predetermined single crystal base material is prepared and an AlGaN layer is epitaxially formed on the AlN template substrate by using a MOCVD technique to grow to a thickness of not less than 900 nm (see for example Y. Kida, T. Shibata, H. Miyake, and K. Hirayama "Metalorganic Vapor Phase Epitaxy Growth and Study of Stress in AlGaN Using Epitaxial AlN as Underlying Layer," Jpn. J. Appl. Phys. Vol. 42 (2003) pp. L572-L574). Such a thickness of 900 nm is a thickness much greater than a critical film thickness of tens of nanometers for crack generation which is theoretically expected.

Semiconductor layered structure and its method of formation, and light emitting device