A hole in a sample from which a sample piece has been extracted with a focused ion beam is filled at high speed using ion beam gas assisted deposition. A method of filling the hole by using the ion beam includes a step of irradiating the hole formed in a face of the sample with the ion beam to thereby form an ion beam gas-assisted deposition layer in the hole. The ion beam gas-assisted deposition layer is formed in the hole while controlling the area to which the ion beam is irradiated so as to cause the ion beam to fall on a part of a side wall of the hole and to not fall on another part of the side wall in an area scanned with the ion beam. The filled hole may then be covered with a protective film.

The present invention relates to a technique of inspecting an electronic device and, more particularly, to a technique of fabricating and observing an electronic device, such as a semiconductor device, by using an ion beam.
In fabrication of electronic devices, such as a semiconductor memory (typified by a dynamic random access memory (DRAM)), a microprocessor, a semiconductor device, such as a semiconductor laser, and a magnetic head, manufacture at a high yield is demanded.
Reduction in the product yield due to occurrence of a defect causes deterioration in profitability. Consequently, it is a big task to discover a failure, a foreign matter, and poor processing as causes of a defect early and to take an early countermeasure. For example, at a manufacturing site of a semiconductor device, energies are put into early defect discovery by a careful inspection and analysis of the cause of the defect. In a process of fabricating actual electronic devices using a substrate, a completed substrate is inspected, the cause of an abnormal part, such as a defect in a circuit pattern or a foreign matter, is pursued, and a countermeasure is examined.
Usually, a high-resolution scanning electron microscope (hereinbelow, abbreviated as SEM) is used for observing a detailed structure of a sample. As the packing density of a semiconductor increases, it is becoming impossible to observe an object using the resolution of the SEM, and a transmission electron microscope (hereinbelow, abbreviated as TEM) having a higher observation resolution is used in place of the SEM.
Fabrication of a conventional sample for a TEM includes extracting a small piece from a sample by cleavage, cutting, or the like. In the case where a sample is a substrate, in most cases, the substrate has to be cut.
Recently, there is an example of using a processing method of irradiating a sample with an ion beam so that particles making up the sample are discharged from the sample by a sputtering action, that is, using a focused ion beam (hereinbelow, abbreviated as FIB) process.
According to the method, first, a rectangular-shaped pellet in the sub-millimeter range, including an area to be observed, is cut out from a sample, such as a substrate, by using a dicer, or the like. Subsequently, a part of the rectangular-shaped pellet is processed with an FIB so as to thin-out the film, thereby obtaining a TEM sample. The feature of the FIB-processed sample for TEM observation is that a part of the sample is thinned-out to a thin film having a thickness of about 100 nm so as to be able to be observed using the TEM. Although the method enables a desired observation part to be positioned with precision of a micrometer level and observed, the substrate still has to be cut.
As described above, although the advantage of monitoring a result of a process during fabrication of a semiconductor device or the like is big from the viewpoint of yield management, the substrate is cut in the fabrication of the sample as described above, and the piece of the substrate is not subjected to the following process, but is instead discarded. Particularly, in recent years, the diameter of wafers has increased in order to lower the unit price of fabricating a semiconductor device. To be specific, the number of semiconductor devices which can be fabricated from one wafer has increased, thereby reducing the unit price. However, the price of each wafer has increased, and the number of semiconductor devices which are lost by discarding a wafer has also increased. Therefore, the conventional inspection method that includes cutting of a wafer is very uneconomical.
Addressing this problem, there is a method capable of obtaining a sample without cutting a wafer. The method is disclosed in Japanese Patent Application Laid-Open No. 05-52721. According to the method, as shown in FIG. 2A, the posture of a sample 2 is kept so that the surface of the sample 2 is irradiated with an FIB 1 at a right angle, and a rectangular area in the surface of the sample 2 is scanned with the FIB 1, thereby forming a rectangular hole 101 having a required depth in the surface of the sample 2. As shown in FIG. 2B, the sample 2 is tilted and a bottom hole 102 is formed. The tilt angle of the sample 2 is changed by a specimen stage (not shown). Subsequently, the posture of the sample 2 is changed and, as shown in FIG. 2C, the sample 2 is set so that the surface of the sample 2 becomes perpendicular to the FIB 1 again, and a trench 103 is formed. A manipulator (not shown) is driven to make the tip of a probe 3 at the end of the manipulator come into contact with a part to be separated in the sample 2, as shown in FIG. 2D.
As shown in FIG. 2E, while supplying a deposition gas 5 from a nozzle 104 for delivering gas, an area including the tip portion of the probe 3 is locally irradiated with the FIB 1, thereby forming an ion beam gas assisted deposition layer (hereinbelow, simply called deposition layer 4). The separation part in the sample 2 and the tip of the probe 3 which are in contact with each other are connected by the deposition layer 4. As shown in FIG. 2F, the remaining part is cut with the FIB 1 and a micro sample 6 as a separate sample is cut out from the sample 2. The cut-out separate sample 6 is supported by the probe 3 connected as shown in FIG. 2G. The micro sample 6 is processed with the FIB 1 and an area to be observed is wall-processed, thereby obtaining a TEM sample (not shown).
As described above, the method is a method of separating a micro sample including a desired area to be analyzed from a sample, such as a wafer, by using the FIB process and means of carrying the micro sample. By introducing the micro sample separated by the method into various analyzers, analysis can be made.
The method of cutting out a micro sample for inspection from a sample without cutting a wafer and allowing the wafer to be continuously subjected to the following process is disclosed in Japanese Patent Application Laid-Open No. 2000-156393. According to this method, there is no semiconductor device which is lost when a wafer is cut, so that total fabrication cost of semiconductor devices can be reduced.
In fabrication of electronic devices as described above, in the case of allowing the wafer to be subjected to the next process, a process for forming hole from which the micro sample is taken out is necessary. In other words, when the formed hole is not processed, the following problems occur.
(1) An end of the hole is broken off and becomes a contamination source. (2) The hole causes an uneven shape of the wafer at the time of spin coating, polishing, or the like. (3) Dusts gather in the hole. For example, in the case of performing CMP (Chemical & Mechanical Polishing) after taking out a micro sample, CMP grains enter the hole and all of these grains cannot be taken away by cleaning. In any processes after performing CMP, a CMP grain can come out of the hole and become foreign matter or cause impurity contamination, which fluctuates device characteristics.
A method related to the technique of putting a wafer subjected to an FIB process back into a process line is disclosed in Japanese Patent Application Laid-Open No. 6-260129. According to this method, in order to put a sample irradiated with a focused ion beam using gallium as an ion source back into a process, either a part to which gallium has been implanted is removed by using an ion beam of a gaseous element which does not exert a conspicuous influence on the characteristics of a sample, or an organic metal film is deposited using an energy beam so as to cover a portion in which gallium is implanted. Specifically, an area to be processed and observed is cleaned by using any of argon, oxygen ions, and oxygen radicals, a compound is deposited and, after that, the sample is put back into the fabrication process.
In an instrument of the method, however, Ga contamination is considered, but a process for addressing an opened hole is not considered.
A method related to the technique of putting a wafer back into a process line after a cross section inspection is disclosed in Japanese Patent Application Laid-Open No. 10-116872. In the disclosed method, a cross section of a wafer is inspected during a semiconductor device process. A hole opened for obtaining the section is filled with an insulator or a conductive film by energy-beam-induced CVD (Chemical Vapor Deposition, although a technical term of CVD is conventionally used, gas-assisted deposition is used as a synonym), or is filled with a desired film by applying a liquid material and irradiating the material with an energy beam. The wafer is put back to a fabrication process line, and the fabrication is continued. Particularly, it is disclosed that a wafer is taken out, a cross section inspection is performed, and the inspected part in the wafer is planarized with an ion beam.
International Publication Number WO 99/17103 discloses a method of covering a hole opened with an FIB with a dielectric by using an ion beam.
However, the conventional hole filling method after the FIB process has the following problems.
First, in the case of filling a hole by the energy-beam-induced gas-assisted deposition, the following problems occur depending on the kinds of beams.
(1) In the case of forming a film by applying a liquid material and irradiating the material with an energy beam, when a film is thick, a crack occurs in the film in a process of irradiating the material with the energy beam. If the wafer is subjected to the following process, it is feared that a piece from the crack can disperse and cause a defect. The depth of an opened hole from which a micro sample is taken out is generally at least 3 to 5 micrometers. On the other hand, the thickness of a film which can be formed without a crack from an oxide film material which is generally used as the liquid material is at most 1 to 2 micrometers. A crack can occur during a heating process in an oxide film applied thicker than that. (2) In laser-beam-induced gas-assisted deposition, a film grows isotropically, so that it is difficult to fill a hole so that the surface is flat. (3) In argon ion beam induced gas-assisted deposition, the beam size in an inexpensive ion emitting system is generally 50 to 500 micrometers. On the other hand, the size of a hole is at most 20 micrometers. It is therefore difficult to form a film only in the hole, but instead a film is formed not only in the hole but also over the periphery of the hole. Thus, it is difficult to fill the hole while realizing a flat surface. (4) In electronic beam induced gas-assisted deposition, deposition speed is generally low and it is difficult to fill the hole within practical time such as within 10 minutes.
(5) In gallium FIB induced gas assisted deposition, a deposition layer can be formed in the hole, but there is a problem such that gallium is taken into the deposition layer. Further, by a sputtering action by FIB irradiation, pieces of gallium and a sample are spread also to areas other than the FIB processed area. The possibility of the gallium contamination causing defects in the fabrication of semiconductor devices is high. Specifically, when nothing is done to address the contamination, and the wafer is subjected to the following process, gallium is diffused and enters a semiconductor device when subjected to the fabrication process, and problems such as poor electric characteristics and poor contacts occur. From the viewpoint of filling a hole at high speed, although the speed is faster as compared with the electron beam induced gas-assisted deposition, it is still difficult to fill the hole within a practical time, such as 10 minutes. Since the absolute amount of a deposition layer can be increased in proportion to an FIB current, then in order to increase the speed of filling a hole, the FIB current is increased. However, when the FIB current is increased to a high current of about 1 nA or higher, the deposition layer forming efficiency deteriorates. The deposition amount and the sputtering amount become almost equal to each other, so that growth of the deposition layer is stopped and a hole cannot be filled at high speed.
Consequently, for improvement in the yield of a semiconductor device and the like, to conduct an inspection during a process without cutting a wafer, the following techniques are demanded, such as a technique of filling at high speed a hole from which a micro sample has been taken out or a hole opened for inspecting a section, while achieving surface flatness. It is also demanded to establish a hole filling method by which a foreign matter is not generated and gallium contamination does not cause a defect in a semiconductor device, so that a problem does not occur in the subsequent processes, and to develop an apparatus capable of realizing the method.
Particularly, from the viewpoint of putting an inspected wafer back into a fabrication line, it is important to shorten the time required to inspect the wafer and put the wafer back into the fabrication line. In other words, a technique for increasing the speed of filling a hole is demanded, and the conventional methods do not address this demand. For example, a technique is desired that is capable of filling a hole at high speed with an increased deposition amount, and without deteriorating a deposition layer forming efficiency, even when the FIB current is increased, specifically, to a high current of about 1 nA or higher.

Refilling method by ion beam, instrument for fabrication and observation by ion beam, and manufacturing method of electronic device


A back side illuminated image sensor includes a pixel array including semiconductor material, and image sensor circuitry disposed on a front side of the semiconductor material to control operation of the pixel array. A first pixel includes a first doped region disposed proximate to a back side of the semiconductor material and extends into the semiconductor material a first depth to reach the image sensor circuitry. A second pixel with a second doped region is disposed proximate to the back side of the semiconductor material and extends into the semiconductor material a second depth which is less than the first depth. A third doped region is disposed between the second doped region and the image sensor circuitry on the front side of the semiconductor material. The third doped region is electrically isolated from the first doped region and the second doped region.

Field of the Disclosure
The present invention relates generally to semiconductor devices. More specifically, examples of the present invention are related to image sensors with enhanced quantum efficiency.
Background
Image sensors have become ubiquitous. They are widely used in digital still cameras, cellular phones, security cameras, as well as, medical, automobile, and other applications. The technology used to manufacture image sensors, has continued to advance at great pace. For example, the demands of higher resolution and lower power consumption have encouraged the further miniaturization and integration of these devices.
One type of image sensor, the complementary metal oxide semiconductor (CMOS) image sensor, is very popular in commercial electronics. However, as these semiconductor devices have scaled downward, photodiode area has also decreased resulting in a lower incident photon count on each photodiode. Several challenges for down-scaled CMOS image sensors are maintaining low-light sensitivity and reducing image noise—two problems exacerbated by a low incident photon count.
The use of conventional light filter arrays (e.g. red, green, and blue arrays) arranged in known patterns (such as a Bayer pattern or the like) may result in decreased light absorption by the image sensor. This is the product of each light filter only permitting the passage of a small range of visible wavelengths. For instance, a red light filter may permit passage of 750 nm-650 nm photons, but block out the remainder of the visible spectrum. Similarly, a green filter may permit the passage of 500 nm-600 nm photons, but block out the remainder of the visible spectrum. As such, the use of conventional light filter arrays may provide for relatively inefficient absorption of visible photons incident on the image sensor. Similarly, a green filter may permit the passage of 500 nm-600 nm photons, but block out the remainder of the visible spectrum. As such, the use of conventional light filter arrays may provide for relatively inefficient absorption of visible photons incident on the image sensor.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.

Image sensor with enhanced quantum efficiency


A steam cleaner includes a housing, a head cleaning member fitted to an upper end opening of the housing, an electric heater received in the housing, a pump also received in the housing, and a water container secured to the bottom of the housing. The pump has an inlet connected to the water container, and an outlet connected to a water pipe passing through the electric heater. A nozzle is connected to the upper end of the water pipe. When the pump and the heater are activated, the pump forces the water in the container through the water pipe for allowing the water to be heated to become steam by the electric heater. The steam is sent out via both the nozzle and the head member to help kill bacteria when the head member is rubbed against an object in cleaning.

The present invention relates to a steam cleaner, and more particularly, to a steam cleaner which takes the form of a combination of a steam producing equipment and an ordinary mop so as to be able to kill the bacteria when it is used for cleaning an object.
Mops are used for washing floors, cars etc, and consist of a long stick with threads of thick string or a piece of sponge. The threads of thick string and the sponge are soaked with water before the mops are used. However, the mops can only remove dirt from the floor or the car without killing the bacteria. To be able to kill the bacteria while cleaning, the mops have to be soaked with water, into which detergent is added. However, the detergent is likely to harm the user""s hands and pollute the environment. Other cleaning equipments such as brushes for washing nets and screen windows have the same disadvantages.
Therefore, it is a main object of the present invention to provide a steam cleaner, which consists of a steam producing equipment and an ordinary cleaner so as to be able to kill the bacteria with the steam when the cleaner is rubbed against an object to remove the dirt.
It is another object of the present invention to provide the steam cleaner with a safety switch such that the steam producing equipment can automatically be cut off when overheats.
It is a third object of the present invention to provide a filter to the steam cleaner for removing the impurity of the water so as to prevent the impurity from blocking the nozzle.
It is a fourth object of the present invention to provide a removable extension holding rod to the steam cleaner for allowing the user to hold the cleaner in cleaning.
The steam cleaner of the present invention includes a housing member, an electric heater, a nozzle, a pump, a filtering member, a head cleaning member and a water container. The housing member has a handle, an upper end opening and a lower base part. The base part has a first and a second connecting holes, and a connecting part having a hole communicating with the first connecting hole.
The electric heater is positioned in the housing member, and electrically connected to a switch fitted on the housing member. The nozzle is connected to the upper end opening.
The pump is positioned in the housing member, and electrically connected to the switch. The pump has an inlet connected to the second connecting hole of the base part, and a water pipe is connected to an outlet of the pump. The water pipe is passed through the electric heater to communicate with the upper end opening.
The filtering member is secured to the base part, and has an inlet connected to the first connecting hole and an outlet connected to the second connecting hole. The head member is connected toe upper end opening of the housing, and can take various forms such as a round brush and the head of a mop to suit different needs.
The water container is secured to the connecting part from a top cap thereof. The cap has a hole for allowing water in the container to be forced through the cap hole, the hole of the connecting part, the inlet of the filtering member, the filtering member, the inlet of the pump, and the water pipe in sequence when the switch is pressed so as to activate the pump and the heater.
Thus, the water forced through the water pipe is heated to become steam by the heater and sent out via the head member to kill bacteria when the head member is rubbed against an object in cleaning.


A packaging machine under control of an electronic control system is set forth. The packaging machine includes a plurality of servo driven packaging stations that execute the processes required to fill and seal a carton. Each of the packaging stations is driven by one or more servomotors associated therewith. A plurality of servo amplifiers are connected to the servomotors to control the rotational movement of the servomotors thereby to effect control of the motion of the various components associated with each if the packaging stations. The packaging machine further includes at least two programmable devices connected for communication over a common bus. A programmable axis manager (PAM) is connected to control the plurality of servo amplifiers and, thus, the motion profiles of the servomotors and components of the respective processing station. A programmable logic controller (PLC) is connected to receive and transmit input/output signals associated with the plurality of packaging stations. The PAM and the PLC communicate data variable values over the common bus using predetermined fingerprints assigned to each variable value. Use of the fingerprint/variable value protocol allows high speed communication between the PLC and PAM thereby allowing the PLC and PAM to be viewed as a single control unit.

Packaging machines are known that integrate the various components necessary to fill and seal a container into a single machine unit. This packaging process, generally stated, includes feeding carton blanks into the machine, sealing the bottom of the cartons, filling the cartons with the desired contents, sealing the tops of the cartons, and then off loading the filled cartons for shipping. The motion and I/O control of the packaging machine may be undertaken by an electronic control system.
Traditionally, control systems for packaging machines have utilized programmable logic controllers (PLC) to effect both motion and I/O control. PLC system architecture, however, is principally directed to I/O control and has only limited value as an axis controller. Such a system is described in U.S. Pat. No. 5,177,930, issued Jan. 12, 1993. As illustrated in the '930 Patent, a single PLC is utilized to control both the motion and the I/O.
Trends within the field of packaging machines point toward increasingly high capacity machines intended for rapid, continuous filling and sealing of a very large number of identical or similar packaging containers, e.g., containers of the type intended for liquid contents such as milk, juice, and the like. One such machine is disclosed in U.S. Ser. No. 08/190,546, filed Feb. 2, 1994, which is hereby incorporated by reference. The machine disclosed in the '546 application includes a plurality of processing stations, each station implementing one or more processes to form, fill, and seal the containers. Each of the processing stations is driven by one or more servomotors that drive the various components of each of the processing stations.
The increased throughput and decreased size requirements have increased the demands that are placed on the control systems that are employed. As the number of axes increases, the demands on the speed of the control system response also increases. The traditional single PLC control system is often inadequate to meet these speed requirements. Accordingly, a more sophisticated control system for a packaging machine of the foregoing type is desirable.


In a semiconductor memory device, two sense amplifiers are provided on one output signal line for reading data stored in a memory cell. The sense amplifiers are connected in parallel to each other. A control signal generation circuit generates a control signal so that one of the sense amplifiers which has a greater drive capability is activated during a predetermined time period after an address from which data are to be read out is changed, and that the sense amplifier having a smaller drive capability is activated during a time period other than the predetermined time period.

1. Field of the Invention
This invention relates to a semiconductor memory device such as a mask ROM (Read Only Memory), an EPROM (Erasable Programmable ROM) or an SRAM (Static Random Access Memory), and more particularly relates to a semiconductor memory device having an improved data read circuit.
2. Description of the Prior Art
In a semiconductor memory device, since data read out from a memory cell is a weak signal, the signal is amplified on an output signal line by a sense amplifier and then output. If the sense amplifier is always in an active state, the power consumption of the semiconductor memory device becomes too large. Therefore, in a conventional mask ROM or the like, after data read out from a memory cell is amplified by a sense amplifier and the read-out data becomes valid internally, the valid data is latched in a latch circuit. Thereafter, the sense amplifier is in an inactive state until the next read, whereby the power consumption is reduced.
A data read circuit in a mask ROM of the above-mentioned configuration is shown in FIG. 7. A memory cell 1 is arranged at each crossing of a number of word lines 2 and bit lines 3. Data stored in the memory cell 1 is input into a sense amplifier 6 through a bit line 3 via an FET 5 which is controlled by a column selection line 4. The data S.sub.OUT amplified by the sense amplifier 6 is latched in a latch circuit 7 and output via an output circuit 8 as output data D.sub.OUT of the ROM.
In this case, the sense amplifier 6 and the latch circuit 7 receive a sense signal .PHI..sub.SA and a latch signal .PHI..sub.LT from a timing generator (TG) circuit 9, respectively. As shown in FIG. 8, when the TG circuit 9 detects the change of an address signal A, the sense signal .PHI..sub.SA becomes High to activate the sense amplifier 6. The latch signal .PHI..sub.LT is at a High level during a short time period after the read-out data becomes valid internally, so as to allow the latch circuit 7 to latch the data S.sub.OUT output from the sense amplifier 6. When the data S.sub.OUT is latched at the rise of the latch signal .PHI..sub.LT, the sense signal .PHI..sub.SA returns to Low so that the sense amplifier 6 is inactivated, whereby the power consumption of the sense amplifier 6 is suppressed until the next read. The read-out data latched in the latch circuit 7 can be output from the output circuit 8 as the output data D.sub.OUT for a predetermined period.
However, in the above configuration, in the case where the address signal A does not change at the first access after the power source V.sub.cc is turned on as shown in FIG. 9, the TG circuit 9 can not output the sense signal .PHI..sub.SA and the successive latch signal .PHI..sub.LT, so that the output data D.sub.OUT continues invalid. In this case, the operation must be performed in such a complicated manner that a dummy cycle is carried out in order to change the address signal A after power is turned on, and then the regular address signal is output as shown in FIG. 10.
In the above-mentioned configuration in which the data read from the memory cell 1 is latched in the latch circuit 7 once and then output, when erroneous data is latched by a noise on a power supply line etc., the erroneous data is output as the output data D.sub.OUT, without conversion.
As described above, a conventional semiconductor memory device has problems in that it requires a dummy cycle when the system is powered on, in order to suppress the power consumption of the sense amplifier 6, and that the probability of a data read error is prone to increase.

Sensing amplifier circuit for data readout from a semiconductor memory device


A fuel filter includes a pair of housing portions defining an interior cavity. A pipe in the housing includes a central flow passage and an opening along the length of the pipe. An exterior groove is also provided in the pipe. A latch device with discrete fingers closely surrounds the pipe and is engageable with the groove to prevent the latch device from moving axially along the pipe. The latch device has an annular sleeve, radially-outwardly spaced from the fingers. A moveable valve device also surrounds the pipe and has a sleeve which normally covers the opening in the pipe. An annular base projects radially outward from the sleeve of the valve device and includes radially projecting tabs defining a plurality of slots. A filter element is removeably located in the housing and has an end cap with a valve-actuating portion. The valve-actuating portion includes a cylindrical portion and an annular base projecting radially inward from the cylindrical portion. A plurality of thin, flat keys are spaced around the valve-actuating portion and project radially inward from the cylindrical portion and axially outward from the base. The keys have first portions which project through the slots in the valve device and engage the sleeve of the latch device to unlock the latch device from the pipe, and second portions which engage the base of the valve device and move the valve element to uncover the opening in the pipe, when the element is inserted into the housing.

This invention relates to fluid filters, and more particularly to fuel filters for vehicles.
Many types of fuel filters (also referred to as xe2x80x9cseparatorsxe2x80x9d) are known in the prior art. A popular type of fuel filter has a housing that encloses a replaceable ring-shaped filter element. The filter element ensures that impurities are removed from fuel before it is delivered to system components such as fuel injection pumps and fuel injectors. Mating portions of the housing form an interior enclosure for the element, and the housing portions may be separated for replacement of a spent filter element. Periodic replacement of the filter element is required so that the filter element will not become so loaded with impurities that fuel flow is restricted. Cost and ease of manufacture have been important considerations with such elements. However, problems may arise when such filter elements are replaced.
One problem is that filter elements with different sizes and/or filtration capabilities often have identical mounting configurations and can fit on the same filter head. However, use of the wrong filter can cause poor engine performance and allow undesirable amounts of contaminants to pass through the fuel system.
Another problem is that individuals may remove a spent filter element and simply re-attach the housing portions without a fresh element. While the engine may operate (at least for a short period of time), this can be detrimental to the engine.
A still further problem is that disturbance of the spent element during replacement may cause collected impurities to fall off the element. In some designs, these impurities may pass into the outlet of the filter housing and reach the components downstream in the fuel system.
To reduce and at least partially eliminate these problems, the filter assembly shown in U.S. Pat. No. 4,836,923, owned by the Assignee of the present application, was developed. This filter includes a unique replaceable filter element that is attached to a removable cover. The housing has an internal standpipe with an opening at the top end. When the element is removed from the housing, the fuel level in the housing falls below the opening in the standpipe. As a result, the impurity-laden fuel left in the housing is less likely to reach the outlet. Likewise, when a new element is installed in the housing, only fuel that has been purified by passing through the media of the element is enabled to reach the opening and pass out of the housing.
While this filter design has many advantages, if the filter element is not removed carefully, impurity-laden fuel in the housing or from the outer surface of the element may fall into the opening in the standpipe. If this happens, some impurities may still reach the downstream components of the fuel system.
In addition, the cover is discarded with each spent element. This is undesirable from a conservation and solid waste standpoint. It is generally desirable to minimize the amount of material discarded, particularly if a discarded element must be treated as hazardous waste. The cover also represents a portion of the cost of the replacement element. As a result this design adds cost to the replacement element. Further, the element may be separated from the cover, and the cover re-attached to the housing without a fresh element also being installed. As such, it still does not fully address the problems associated with operating an engine without a filter element installed.
A further improved filter is shown in U.S. Pat. No. 5,770,065, also owned by the assignee of the present application. In this filter, the filter element is received around a standpipe extending centrally in the housing. A spring-biased valve element internal to the standpipe is normally closed, and can be engaged and moved to an open position by a projection on the element when the element is properly installed in the housing. This filter provides the advantages of the ""923 patent, as well as prevents inpurity-laden fuel from passing through the standpipe when the element is changed. The assembly also prevents operation of the engine without an appropriate element in place.
The filter shown in the ""065 patent has received wide-spread acceptance in the marketplace. Nevertheless, it is believed that there exists a need for a still further filter which has the advantages of the ""065 patent, but where the valve structure is located exterior to the standpipe. Such a valve structure can be easier to manufacture and assemble, thereby reducing the cost of the assembly. It is also believed there is a demand for a filter where the opening into the standpipe is located toward the lower end of the filter. This can prevent or at least reduce the chance of pulling air into the system, as the opening is kept below the level of the fuel.
As such, it is believed that there exists a need for a further improved fuel filter which overcomes at least some of the above-described drawbacks.
A new and unique fuel filter is provided that prevents an improper filter element from being used in the filter and prevents operation of the filter without a filter element in place. The filter is simple and low-cost to manufacture and assemble, and prevents air from entering the system.
According to the present invention, a pipe extends centrally within the housing, and a valve structure is provided externally to the pipe. In one embodiment, the pipe is a standpipe fluidly connected to the outlet port; while in another embodiment the pipe is an inlet pipe to a fuel pump in the housing. In either embodiment, the pipe includes a central fluid passage and an opening into the passage toward the lower end of the pipe. A radially-outward facing groove or channel is provided circumferentially around the pipe, near the opening.
The valve structure for the filter includes a valve device and a latch device. The valve device has a sleeve closely surrounding the pipe, and an annular, radially-outward projecting base surrounding the sleeve. A series of radially-outward projecting tabs are spaced around the periphery of the base. The valve device can be easily manufactured unitarily in one piece from inexpensive material, such as plastic.
The latch device for the valve structure includes a series of deformable fingers in an annular array closely surrounding the pipe. The distal ends of the fingers are normally aligned with and engage the groove in the pipe to prevent the latch device from moving axially along the pipe. The latch device, in the locked position, supports the valve device in a position such that the valve sleeve blocks flow through the opening in the pipe. The latch device further includes an annular sleeve radially outwardly-spaced from the fingers. One end of the sleeve, located away from the valve device, is connected to the fingers, while the other end of the sleeve, located adjacent the valve device, defines an annular engagement surface. The latch device likewise can be easily manufactured in one piece from inexpensive material, such as plastic.
According to the first embodiment, the housing is designed for a xe2x80x9ctop-loadedxe2x80x9d element, and includes a removable lid. In this embodiment, the latch device is located between the valve device and the lower end of the housing, with the annular engagement surface of the latch device facing upwardly in the housing and against the base of the valve device.
In the second embodiment, the housing is designed for a xe2x80x9cbottom loadedxe2x80x9d element, and the latch device is located between the valve device and the pump, with the annular engagement surface of the latch device facing downwardly in the housing, and against the base of the valve device.
In either embodiment, a compression spring surrounds the pipe and urges the latch device toward the valve device.
The filter element for the fuel filter includes a ring of filter media circumscribing a central axis and having upper and lower end caps. Each end cap has an annular portion bonded to the end of the filter media. The lower end cap further has an axially-extending cylindrical portion connected to and bounding the inner diameter of the annular end cap portion, and an annular base projecting radially-inward from the cylindrical portion. The annular base closely surrounds the sleeve of the valve device in the first embodiment, and the inlet pipe in the second embodiment.
A plurality of thin, flat keys are provided internally of the cylindrical portion of the lower end cap. The keys project radially inward from the cylindrical portion toward the central axis, and axially away from the annular base. The keys project axially-outward (i.e., downward) from the media ring in the first embodiment (the xe2x80x9ctop-loaded designxe2x80x9d), and axially-inward (i.e., upward) into the media ring in the second embodiment (the xe2x80x9cbottom-loadedxe2x80x9d design). The keys preferably include a step defining an axially longer and radially thinner portion, and an axially shorter and radially wider portion. The lower end cap, including the cylindrical portion, base and keys, is also preferably formed unitarily, in one piece from inexpensive material, such as plastic.
In the first embodiment, when the filter element is inserted from the upper end of the housing, the keys of the lower end cap are received downwardly between the tabs on the valve device. The longer portions of the keys engage the upward-facing engagement surface on the latch device and cause the latch device to bend, which in turn causes the fingers to move radially outward from their locking engagement with the groove in the standpipe. At the same time, the shorter portions of the keys engage the base of the valve device and cause the valve device to move downwardly along the standpipe, against the latch device and out of blocking relation with the opening in the standpipe. When the element is properly positioned in the housing, the opening to the standpipe is completely open to allow fuel flow through the fuel filter.
In the second embodiment, when the element is bottom-loaded, the keys of the lower end cap are similarly received between the tabs on the valve device, with the longer portions of the keys engaging the downward-facing engagement surface on the latch device. This similarly causes the latch device to bend, and the fingers to move radially outward from their locking engagement with the groove in the pipe. The shorter portions of the keys at the same time engage the lower surface of the base of the valve device and cause the valve device to move upwardly along the pipe (against the latch device), uncovering the flow opening in the pipe. When the element is properly positioned in the housing, the opening to the inlet pipe is completely open to allow flow through the filter assembly.
The dimensions, number and location of the keys on the lower end cap and the tabs on the valve device can be selected to allow only a specific filter element to be used with a particular housing. An incorrect geometry, number or arrangement of keys and/or tabs will prevent a filter element from being properly located in the housing. The keys and tabs are relatively easy to fabricate, using simple molding operations.
Once a filter element with a proper selection of keys is installed in the housing, fluid can be provided into the housing and pass through the filter media ring to be filtered. When the element is to be replaced, the spring assists in removing the element from the housing, and returns the valve device to a position blocking the opening in the pipe. This prevents unfiltered fuel and contaminants from passing through the pipe and downstream in the system. The location of the opening in the lower end of the pipe is below the typical level of fuel in the housing, which prevents air from passing downstream through the system.
The valve device and latch device are easily assembled over the standpipe and inlet pipe during assembly of the filter housing.
Thus, as described above, the filter of the present invention provides many of the benefits of the prior art filters such as preventing an improper element from being installed within the housing, and preventing operation of the filter without and element in place. In addition, the filter is simple and low cost to manufacture and assemble, and prevents air from entering the system.
Further features and advantages will be apparent upon reviewing the following Detailed Description of the Preferred Embodiment and the accompanying Drawings.

Filter cartridge for a fuel filter having a keyed latch shut-off valve


A processed DRI material having an average surface roughness (Ra) of less than 1.5 μm is disclosed. A method and system for making processed DRI are also disclosed. One embodiment of the method and system may include assembling a rotatable chamber having an internal screen capable of supporting DRI during tumbling, with at least one opening in the chamber to permit fines to exit the chamber during tumbling, and delivering DRI into the chamber to tumble the DRI on the screen to remove fines from the DRI. Another embodiment of the method and system may include assembling a rotatable chamber having a feed end and an exit end, and having a screen therein capable of supporting DRI as the DRI moves through the chamber, and delivering DRI to the chamber and rotating the chamber to tumble the DRI while removing fines.

The present disclosure relates to a system and method for making direct reduced iron. Direct reduced iron (DRI), sometimes called sponge iron, is a commercial product widely used as a source material for making steel. The conventional techniques for making steel involve the use of an electric arc furnace (EAF) or a basic oxygen furnace (BOF). DRI is typically higher in iron units than taconite pellets and other sources of iron, and can be used as a partial substitute for scrap in the production of steel by EAF.
DRI is formed from beneficiated iron ore, such as taconite pellets. For example, taconite has been mined and crushed, and the iron containing portions magnetically separated from the non-iron containing portions to form a beneficiated product higher in iron content than mined taconite. The beneficiated iron ore portion may be formed into pellets by pelletizing, and heated in a linear hearth furnace in the presence of reducing agent (e.g., carbonaceous material) to a temperature below the melting point of iron using natural gas or coal, to promote the reduction of iron ore to metallic iron. DRI is typically above 90% metallic iron with the remainder gangue.
In the process to make DRI, the beneficiated and pelletized iron oxide containing material is moved through a furnace mixed with a reducing agent, such as coal, coke, or another form of carbonaceous material. A desulfurizing agent, such as limestone or dolomite, is also typically added. The carbon of the reducing agent and the oxygen of the iron oxide material react chemically in the reducing zone of the furnace, thereby partially reducing the iron oxide to form metallic iron. This, and other traditional reducing processes, are used to create the DRI.
DRI is difficult to transport because DRI and DRI fines are highly reactive with oxygen in air and moisture. Moisture, in particular, reacts with the iron forming FeO and H2. The DRI being sponge iron has many voids making it porous in nature. The porous nature of DRI also means that it has low compressive strength, and handling of DRI generates surface fines. Additionally, when the DRI is stored, for example in the hold of a ship during transportation, some of the pellets have been prone to disintegrate under the weight of pellets above them further generating fines and small particles. The DRI fines and small particles increased the ability for reaction with moisture and oxygen around it. Additionally, the rough surface characteristics of the DRI pellets produce particulate matter and other fines having a high surface area, which also promoted the likelihood of the DRI reacting with oxygen. Such particulate matter and fines typically are produced throughout the storage and transportation of the DRI, making it difficult to transport DRI over long distances and to store DRI for long periods.
The porous, low internal strength, and flakey nature of DRI all increase the surface area of the nodule that is exposed to an oxidizing atmosphere and/or moisture, resulting in substantial and rapid oxidation and rusting. The reactions that occur during DRI oxidation produce heat and hydrogen making DRI susceptible to overheating and combustion. Increases in temperature in containers storing DRI, in which air is free to circulate, can reach 1200° F. Such combustion causes fires in the holds of ships during transportation of DRI and in the clam buckets of cranes when unloading DRI. These risks have substantially increased the cost of DRI delivered to a steel plant because of the losses during transportation and storage. Due to the difficulties and risks associated with transporting DRI, production of DRI has with a few exceptions been generally located near the steelmaking facilities and near the time of use in steelmaking, rather than in more economical locations and times.
Consequently, various techniques have been used in the past to passivate DRI to reduce the risks associated with its pyrophoric properties and improve its compressive strength. However, despite various attempts there still remains a need for an economic and efficient way of passivating DRI so it can be safely transported over long distances in bulk and stored. A strong, stable and pyrophobic product would enable the safe transport and storage of DRI, dramatically increasing its usefulness and effectiveness in steelmaking.
Presently disclosed are a method and system for making processed DRI. The method comprises assembling a rotatable chamber having an internal screen capable of supporting DRI during tumbling within the chamber, with at least one opening in the chamber adapted to permit fines to exit the chamber during tumbling, and delivering DRI into the rotatable chamber and rotating the chamber to tumble the DRI on the screen in the chamber to remove fines from the DRI. The screen may have a mesh size between ⅛ and ¼ mesh. The method may also include evacuating fines removed from the DRI through the opening or openings in the rotatable chamber during rotation of the chamber, and may include evacuating fines removed from the DRI during tumbling. The DRI may be tumbled in the rotatable chamber at between 20 and 50 or between 20 and 40 revolutions per minute for a residence time of at least 10 minutes in the chamber to produce the desired removal, which is manifested by the DRI having a polished appearance.
The method and system for making processed DRI may also include assembling rotatable rollers downstream of the rotatable chamber adapted to rotate the DRI and applying oil to the processed DRI. Spray nozzles may be positioned and adapted to deliver oil to the processed DRI rotating on rollers. The oil may be mineral oil, and may include oleic acid. The oil may be heated prior to delivery of the oil to the processed DRI.
The method and system for making processed DRI may further comprise applying a material adapted to increase the compressive strength of the DRI to the processed and oiled DRI. The material may include limestone, such as a limestone based binder.
A method and system for making processed DRI is also disclosed that comprises assembling a rotatable chamber having a feed end and an exit end, and having an internal screen capable of supporting DRI during tumbling as the DRI moves through the rotating chamber from the feed end to the exit end and having at last one opening along the chamber to permit fines removed from the DRI during tumbling to exit the chamber, delivering DRI to the rotatable chamber through the feed end and rotating the chamber to tumble the DRI on the screen in the chamber while the DRI moves through the chamber from the feed end to the exit end while removing fines from the DRI, and removing processed DRI from the discharge end of the rotatable chamber.
Also disclosed is a processed DRI material having a surface roughness (Ra) of less than 1.5 μm. Alternatively, the processed DRI material may have a surface roughness (Ra) of less than 1.0 μm, or less than 0.75 μm. The processed DRI material may comprise pellets, and may have a tumble index of greater than 98.5%+¼ after 200 revolutions. In other examples, the processed DRI material may be coated with oil, and the oil may comprise mineral oil and oleic acid. The processed DRI material may also comprise a binder, such as limestone, to increase the compressive strength of the DRI material.
Also disclosed is a processed DRI material having a surface roughness (Ra) of less than 1.5 μm made by the steps of assembling a rotatable chamber having a feed end and an exit end, and having an internal screen capable of supporting DRI during tumbling as the DRI moves through the rotating chamber from the feed end to the exit end and having at last one opening along the chamber to permit fines removed from the DRI during tumbling to exit the chamber, delivering DRI to the rotatable chamber through the feed end and rotating the chamber to tumble the DRI on the screen in the chamber while the DRI moves through the chamber from the feed end to the exit end while removing fines from the DRI, and removing processed DRI from the discharge end of the rotatable chamber.


In a first embodiment, the present invention is a method of detecting an open secondary winding, including the steps of enabling an integrator, resetting the integrator, detecting an ionization current, integrating the ionization current over a spark window, comparing the integrated ionization current with a threshold, and setting an open secondary flag if the integrated ionization current is below the threshold. In another preferred embodiment, the invention is a method of detecting an open secondary winding by measuring spark duration including the steps of comparing an ionization signal with a first threshold, measuring the spark duration when the ionization signal is greater than the first threshold, comparing said spark duration with a second threshold, and setting an open secondary flag.

1. Technical Field
This invention is related to the field of internal combustion (IC) engine ignition systems. More particularly, it is related to the field of detecting an open secondary winding of an ignition coil.
2. Discussion
Typically, an ignition coil and an ignition or a spark plug are disposed in a combustion chamber of an internal combustion engine. The ignition coil includes a primary winding and a secondary winding. The ignition plug is connected in electrical series between a first end of the secondary winding and ground potential. If the spark plug is not connected (as is the case where the secondary is open), no spark will be generated, and part of the charged energy is dissipated through ringing current caused by capacitance between the secondary winding and ground. Since the charged energy is not dissipated by a spark, the fly-back energy dissipated by the IGBT over the primary winding side after the end of charge is much higher than the case when the secondary winding is connected to a spark plug and a spark occurred after the coil was charged. In fact, the total energy dissipated by the IGBT connected to the ignition coil with an open secondary winding could be as great as four times more than when the secondary winding is connected to a spark plug. This indicates that the heat dissipation of the IGBT could be four times more than the normal operational condition. A heat sink is required to protect the IGBT from being overheated for both normal operational and open secondary conditions. This increases cost of the ignition system. However, in some cases the open-secondary condition may be prevented.

Methods of diagnosing open-secondary winding of an ignition coil using the ionization current signal


An integrated circuit having as power supply voltages a low voltage reference, a logic supply voltage reference and a high voltage reference is provided. The high voltage reference is greater than the low voltage reference and the logic supply voltage reference. The integrated circuit includes an electrically programmable non-volatile memory element, and a selection and programming circuit connected thereto. A voltage control device is connected to a power supply input node of the selection and programming circuit for applying, based upon a programming control signal, the high voltage reference for programming the electrically programmable non-volatile memory element or for applying at least one logic supply voltage reference.

The present invention relates to the field of integrated circuits, and more particularly, to a device for controlling a power supply in an integrated circuit comprising electrically programmable non-volatile memory elements.
In the new submicron technologies, the oxide thicknesses are very small, for example 25, 55 or 70 angstroms. An oxide with a thickness of 35 angstroms cannot withstand a voltage over 2 volts. An oxide with a thickness of 55 or 70 angstroms cannot withstand a voltage over 4 volts. Thus, with the new submicron technologies, the integrated circuits receive a lower logic supply voltage at a level optimized to give the best response time in terms of speed while ensuring the reliability of the circuit with protection of the oxides.
In certain integrated circuits, it is possible to have parts of the circuit that use different oxide thicknesses. For improved performance, it may be planned that each part will receive the corresponding optimum supply voltage. It is possible for example to have an integrated circuit with one part that is supplied at 3.3 volts while the other part is supplied at 1.8 volts depending on the thickness of the oxides in each part. Usually, the integrated circuit then receives an external logic supply voltage that is the highest supply level, i.e., 3.3 volts in the example. A voltage divider is provided in the circuit to provide the lowest supply level, 1.8 volts in the example. This divider is such that it is capable of withstanding the highest voltage level.
Integrated circuits based on submicron technologies may comprise an electrically programmable non-volatile memory, such as for example, EEPROM, EPROM, flash EPROM or other similar memories. Memories of this kind use voltage levels, for their programming, that are greater than the logic supply voltages of the integrated circuits. These programming voltage levels depend essentially on the technology considered.
An electrically programmable non-volatile memory element usually comprises at least one floating-gate transistor. The programming of a 0 or a 1 in this element is obtained by the application of appropriate programming voltages to the gate, the drain, the source and the well connection (substrate) of this transistor. In a typical example of an integrated circuit based on submicron technology, the programming voltage levels are 5 volts (drain), 9 volts (gate) and ground (source).
To program these memory elements, it is therefore necessary to have available at least one high voltage that is higher than the logic supply voltages of the integrated circuit. The programming voltage levels needed are produced internally, from this high voltage, by circuitry for the selection and programming of the memory elements. This circuitry includes, for example, a voltage adder or multiplier type circuit.
The integrated circuits typically receive this high voltage permanently at an external pin. Some of the elements of the selection and programming circuitry, and especially their oxides, may receive this high voltage permanently. Depending on the other voltage levels that are applied to them, they may therefore have an excessively high potential at their terminals, and this may be the case frequently or almost permanently. In submicron technologies, the oxides are particularly thin. Even when using the greatest thickness available in the technology considered, it would have to be ensured that each oxide to be protected has a cascode type protection element so that the reliability is not reduced. For reasons of complexity, functionality and cost, an approach of this kind is not satisfactory.
In view of the foregoing background, an object of the present invention is to improve the reliability of such integrated circuits based on submicron technology, with electrically programmable non-volatile memories, by an overall protection device designed at the level of the high voltage pin.
This and other objects, advantages and features of the present invention are provided by a power supply control device such that the elements of the selection and programming circuit associated with the non-volatile memory elements are powered by the logic power voltage at least outside the programming cycle. With a power control device according to the present invention, the selection and programming circuit associated with the non-volatile memory elements are subjected to programming voltage levels only during the programming cycles. For the remainder of the time, they receive the lower level logic power voltage without in any way endangering the submicron oxides. Thus, the time of exposure to the programming voltage levels is significantly reduced. The reliability of the integrated circuits comprising a power supply control device of this kind is greatly improved.
A power supply control device according to the present invention has two voltage selector switches, one to switch over the high voltage and the other to switch over the logic supply voltage to a power supply input node of the selection and programming circuitry associated with the memory elements. These selection switches are controlled in a complementary way by a voltage level translator connected between the high voltage and ground. This translator is controlled by a binary control signal generated internally by the integrated circuit. The active level of this control signal, used to switch over the high voltage, may correspond to a cycle for writing elements of the non-volatile memory. Outside the writing cycle, this control signal is at its inactive level, which is the supply voltage that is switched over to the input supply node of the selection and programming circuitry.
A cycle for writing memory elements typically comprises, for each programming address, a programming operation followed by a read verification. The write signal remains active only during the time of the write cycle, with read and address changing control signals being used to reduce the time of exposure to the high voltages.
In one embodiment, the level translator is sized so that it can switch over at very high speed, so that it is possible to switch over the high voltage at each change in programming address, to carry out the programming operation at this address and then switch the supply voltage over during the read verification of this programming operation. Thus, the time of exposure to the high voltage is reduced to the maximum.
The invention therefore relates to an integrated circuit comprising electrically programmable non-volatile memory elements and an associated selection and programming circuitry. The integrated circuit includes as supply voltages, a ground reference voltage, at least one logic supply voltage and a high voltage. The high voltage is used to give the voltage levels needed for the programming of one or more non-volatile memory elements. According to the present invention, this integrated circuit furthermore comprises a voltage control device applied to a power input node of the selection and programming circuitry to apply either the high voltage or a logic supply voltage as a function of a programming control signal.

Device to control the power supply in an integrated circuit comprising electrically programmable non-volatile memory elements


A power tool (10) includes a power tool housing (18) at least partially-encompassing an internal combustion engine (14) and a harness (12) on which the power tool housing is mounted. The harness has a pair of shoulder straps (16), a waist strap (24), and a panel (44) connecting the shoulder' straps and waist strap. The power tool housing is mounted on a frame (30) having at least one arcuate tool-supporting member with an upper end proximate the shoulder straps and a lower end proximate the waist strap. The tool-supporting member is shaped along its vertical length such that a middle portion of the member arcs away from the panel such that there is an air-circulation space (S) between the power tool housing and the panel. In one embodiment, the power tool is a blower and the housing has an air intake port (46) facing the air-circulation space.

1. Field of Invention
This invention relates generally to the field of lawn and garden tools and, more particularly, to a backpack mounted power tool with a harness that spaces the power tool apart from the operator.
2. Description of Related Art
Yard tools, such as blowers, brush cutters, chemical spreaders and other tools powered by small air-cooled internal combustion engines, are popular among professional grounds keepers as well as the common homeowner. As these tools can be heavy and bulky, it has been known to mount various components of the tool on a backpack frame so that the tool is carried on the back of an operator during work. For example, backpack blowers have been used in lawn and garden applications to enable an operator to direct a stream of high velocity air toward one or more objects to propel the objects along the ground. Such backpack blowers are capable of developing flow velocities and flow volumes greater than the capabilities of ordinary hand-held blowers.
One noticeable problem with many conventional backpack frames for power tools is they are bulky and uncomfortable to wear. Typical backpack-type frames are generally formed from a pipe material and have an L-shape with a pedestal that projects rearwardly to carry the tool. The heavy weight of the tool and the frame itself is a burden on the operator and makes it difficult for the operator to extend and move while using the tool. Additionally, the frame typically maintains the internal combustion engine in close proximity to the back of the operator. This increases the heat felt by the operator and can lead to discomfort.


The present disclosure is directed to systems and methods for mitigating or eliminating the effectiveness of a side-channel based attack, such as one or more classes of an attack commonly known as Spectre. Novel instruction prefixes, and in certain embodiments one or more corresponding instruction prefix parameters, may be provided to enforce a serialized order of execution for particular instructions without serializing an entire instruction flow, thereby improving performance and mitigation reliability over existing solutions. In addition, improved mitigation of such attacks is provided by randomizing both the execution branch history as well as the source address of each vulnerable indirect branch, thereby eliminating the conditions required for such attacks.

Speculative execution is utilized by most modern computing processors to achieve high performance. Such execution allows instructions to be executed prior of knowing that they will be architecturally required by the intended flow of execution. An important part of speculative execution involves branch prediction: instead of waiting for the target of a branch instruction to be resolved, the processor attempts to predict the control flow and speculatively executes the instructions on the predicted path. In many cases, the prediction is correct and boosts execution performance in terms of CPU cycles; when the prediction is wrong, results of the speculatively executed path will be discarded such that no architectural states are impacted.
Side-channel based attacks include any attack based on information gained from the implementation of a computer system, rather than weaknesses in the implemented algorithm itself. Such side-channel based attacks may use timing information, power consumption, electromagnetic leaks, or even sound as an extra source of information that is exploited to obtain information and/or data from the system. Side-channel based attacks include those typically referred to respectively as "Spectre" and "Meltdown," both of which gained widespread notoriety in early 2018 and rely on deducing whether data originates in a cached or un-cached location. To a significant degree, the determination of where data originates relies upon the precise timing of events such as loads from memory space.
A first class of Spectre attack (a "class I" attack) takes advantage of branch target misprediction by a CPU to read data from memory into cache. Upon detecting the misprediction, the CPU clears the data from the pipeline, but the data read into cache remains. A covert side-channel may then be used to obtain the residual data from the cache. In this class of attack, the attacker trains the branch predictor in a system to take a particular branch. For example, using the following instructions, an attacker may train the system by providing values for "x" that are consistently smaller than the size of "array1." The attacker thus trains the system to speculatively execute the subsequent instruction based on the assumption that the branch has been historically true:
if ( x < array1.size( ) ) { int value = array2[array1[x] * 256] // branch 1}After training the system, the attacker sets the cache to a known state and provides a value of "x" that exceeds the size of "array1." Having been previously trained that "x" is typically less than the size of "array1," the processor executes the branch instruction (prior to the processor throwing the exception due to "x" being greater than the size of "array1") and uses the value found at address "x" as an index to look up the value at address "x" in array2. The processor loads the value at address "x" in array2 into cache. The attacker then reads all of the values of array2 and is able to determine the value of "x" as the address in array2 having the shortest access time.
For example, assume array1 has 256 elements addressed "0" to "255." The attacker provides values of "x" between 0 and 255 to train the system that the branch instruction is routinely executed. The attacker then sets the cache to a known state and provides a value of 512 for "x" (i.e., a value greater than 255). The value "01000000" (i.e., "64") at memory location 512 is read. The processor then looks up the value of array2 at address 64*256 and loads the value into cache. The attacker then examines the read time for each element in array2, the read time for element at address 64*256 will be less than the read time for the other array2 addresses, providing the attacker the information that the address at memory location 512 is "01000000" or "64." By performing the action for every memory location, the attacker is able to read the contents of the memory byte-by-byte.
Previous approaches to thwarting or mitigating class I Spectre attacks include attempts to do so via "serializing" instructions (e.g., LFENCE for Intel processor architectures, CSDB for ARM processor architectures, etc.) prior to conditional statements or load instructions. Such approaches generally involve disabling speculative execution entirely until an identified such instruction is completed. However, such approaches result in significant expense in terms of processor clock cycles, as they completely disable speculative execution (and associated efficiencies) every time a serializing instruction is executed.
A second class of Spectre attacks ("class II" attacks) exploit indirect branching by poisoning the Branch Target Buffer (BTB) such that a CPU speculatively executes a gadget that causes the CPU to read data from memory into cache. Upon detecting the incorrect branching, the CPU clears the data from the pipeline but, once again, the data read into cache remains. A covert side-channel may then be used to obtain the residual data from the cache. In this class of attack, the attacker poisons the BTB of the victim system by repeatedly performing indirect branches to a virtual address in the victim's system that contains the gadget. For example, an attacker may control the content of two registers (R1, R2) in the victim's system at the time an indirect branch occurs. The attacker must find a gadget in the victim's system that, upon speculative execution by the victim's CPU, leaks data from selected memory locations in the victim's system. The gadget may be formed by two instructions, the first of which contains an instruction that mathematically and/or logically (add, subtract, XOR, etc.) combines the contents of register R1 with another register in the victim's system and stores the result in R2. The second instruction reads the contents of register R2, storing the value in R2 in cache.
For example, the attacker may control two registers in the victim system, ebx (register R1) and edi (register R2). The attacker then finds two instructions on the victim's system, such as:
adc edi,dword ptr [ebx+edx+13BE13BDh]adc d1,byte ptr [edi]By selecting ebx=m−0x13BE13BD−edx the attacker is able to read the victim's memory at address "m." The result is then added to the value in edi (R2). The second instruction in the gadget causes a read of R2 which contains the sum of "m" plus the attacker's value initially loaded into edi, transferring the value into the cache. By detecting the location of R2 within the cache using a side-channel timing attack, the attacker is able to determine the value of "m."
Previous approaches to thwarting or mitigating class II Spectre attacks include "return trampoline" (also known as "retpoline"), which is a compiler-supported mitigation technique. Retpoline essentially converts each vulnerable indirect branch instruction into (1) a "dummy" call that pushes a safe return address on both the process stack and the return stack buffer ("RSB"); (2) an instruction to overwrite the return address on the process stack with the indirect branch target address; and (3) a "return" instruction to the target address. However, such approaches require both a microcode update (consuming limited microcode patch resources) and operationally expensive operating system (OS) updates. Moreover, such retpoline approaches result in significant performance detriments, as they restrict speculative execution, isolate speculative resources of processing threads, and necessitate flushing of speculative arrays upon security context switches. Furthermore, because retpoline converts all indirect branches into the bifurcated "push and return" operations, it is incompatible with many existing control flow integrity mitigation techniques, such as Control-flow Enforcement Technology (CET), Control Flow Guard (CFG) and Return Flow Guard (RFG) and Reuse Attack Protector (RAP).
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications and variations thereof will be apparent to those skilled in the art.

Efficient mitigation of side-channel based attacks against speculative execution processing architectures


W-type ferrite has improved magnetic properties, in particular, coercive force. A high coercive force (HcJ) and a high residual magnetic flux density (Br) can be simultaneously attained by a ferrite magnetic material comprising an oxide having a composition wherein metal elements Sr, Ba and Fe in total have a composition ratio represented by the formula Sr(1−x)BaxFe2+aFe3+b in which 0.03 ≦x≦0.80, 1.1≦a≦2.4, and 12.3≦b≦16.1. The ferrite magnetic material can form any of a ferrite sintered magnet, a ferrite magnet powder, a bonded magnet as a ferrite magnet powder dispersed in a resin, and a magnetic recording medium as a film-type magnetic phase. As for the ferrite sintered magnet, there can be attained a fine sintered structure that has a mean grain size of 0.6 μm or less.

Magnetoplumbite-type hexagonal ferrites typified by SrO.6Fe2O3, that is, M-type ferrites have hitherto been dominantly used for ferrite sintered magnets. As for such M-type ferrite magnets, efforts have been made to achieve high performance thereof, focusing on that the ferrite grain sizes are made closer to the single domain grain sizes, that ferrite grains are aligned in a magnetic anisotropic direction, and that high densities are achieved in the magnets concerned. As a result of such efforts, the properties of M-type ferrite magnets have approached the upper limits thereof, so that it is difficult to expect drastic improvements of the magnetic properties under the present circumstances.
The W-type ferrite magnet has been known as a ferrite magnet that has potentiality to surpass in magnetic properties the M-type ferrite magnet. The W-type ferrite magnet is higher by about 10% insaturationmagnetization (4πIs) than the M-type ferrite magnet and is of the same order in anisotropic magnetic field as the M-type ferrite magnet. Patent Document 1 (National Publication of International Patent Application No. 2000-501893) discloses a W-type ferrite magnet having a composition represented by SrO.2(FeO).n(Fe2O3), wherein n falls within a range from 7.2 to 7.7, and a sintered body thereof has a mean grain size of 2 μm or less and a (BH)max of 5 MGOe or more.
Patent Document 2 (Japanese Patent Laid-Open No. 11-251127) discloses a W-type ferrite magnet which has a maximum energy product surpassing the maximum energy products of the conventional M-type ferrites and has a composition different from the compositions of the conventional W-type ferrite magnets, wherein the fundamental composition thereof is represented by a formula MO.xFeO.(y−x/2)Fe2O3 (M being one or more of Ba, Sr, Pb and La) with the proviso that 1.7≦x≦2.1 and 8.8≦y≦9.3 in terms of atomic ratios. A magnet disclosed in Patent Document 2 having a composition of SrO.2FeO.8Fe2O3 has properties such that the residual magnetic flux density (Br) is 4800 G, the coercive force (iHc) is 3000 Oe, the maximum energy product ((BH)max) is 5.5 MGOe.
[Patent Document 1]: National Publication of International Patent Application No. 2000-501893
[Patent Document 2]: Japanese Patent Laid-Open No. 11-251127

Ferrite magnetic material and ferrite sintered magnet


An airborne wind energy conversion system with a ground generator and unorthodox power capture or transfer means, including such embodiments as: a system with an ultra-long flexible wing, which serves both for power harvesting and power transfer; a system with a tethered wing, the tether having an airfoil cross section in at least a substantial part of its length and participating in power harvesting; a system with a very long semi-circular wing, harvesting and transferring wind power by its helical motion; a system in which a conventional wing both harvests wind power and excites waves in the tether, the waves transferring the power.

This invention is generally directed to airborne wind energy conversion systems and methods.
The classical work in the airborne wind energy conversion systems (AWECS) is the article by Miles L. Loyd "Crosswind Kite Power" (1979), in which the author disclosed a wind energy harvesting device, comprising a tethered wing, flying cross wind and harvesting wind energy, and transferring harvested energy to a ground based generator via motion of the tether. Crosswind motion of a wing is much more efficient, than downwind motion, allowing the wing to fly many times speed of the wind and harvest energy from an area, many times larger than the area of the wing. The article has also offered two ways of converting harvested mechanical energy into electrical energy.
In one of them, the electrical generator is on the ground and the tether is reeling out, transferring motion to the rotor of the generator. Systems, implementing this method are discussed in the U.S. Pat. Nos. 7,504,741 & 7,546,813 by Wrage et al, U.S. Pat. No. 8,080,889 by Ippolito et al, U.S. Pat. No. 6,523,781 by Ragner. Velocity of the lengthwise motion of the tether must be well below velocity of the wing. In such conditions, the tether is subject to the very high force, requiring thick tethers and creating very large torque in the ground equipment for useful power, thus rendering the whole system uneconomical.
In another method, the generator is airborne and its rotor is coaxial with the propeller, driven by relative air flow. This method is discussed in the U.S. Pat. No. 3,987,987 by Payne et al., U.S. Pat. No. 8,109,711 by Blumer et al. Among shortcomings of this method are large weight of the generator, carried onboard, large weight and limited flexibility of the tether, which is tasked with conducting electrical power from the generator to the ground.
The systems with downwind wing motion or with drag based (i.e., non-airfoil) airborne members are also worth mentioning. One such system is discussed in the U.S. Pat. No. 6,072,245 by Ockels. Aside of the shortcoming of the downwind wing motion, it forces the wings to approach the ground and uses a complex apparatus to prevent collision between the wings and the ground mechanisms.
This invention is directed to solving these shortcomings and providing a cost efficient AWECS. Certain airborne wind energy conversion systems with fast motion transfer were disclosed in PCT/US12/66331 and PCT/US13/30314 by Goldstein. Nevertheless, there is need in larger variety of cost efficient AWECS. This invention is directed to provide such variety.

Airborne wind energy conversion system with ground generator and unorthodox power capture or transfer