Delivery components allow data read, write or operation requests and data responses to pass between a client software application and access components. Each delivery component is developed specifically for each client application. Furthermore, data views (that is, sets of mapping and stored procedures) receive data read. write or operation requests and construct responses, and allow data responses to pass to system domain server components from a target database that is not compatible with the client application. Each set of data views is developed specifically for each target database, and provides virtual compatibility for each target database with each client application. The delivery components and the data views together allow the client application to access the incompatible database through the access components and system domain server components.

Compatibility of data has eluded organizations whose computer systems need to exchange information with other organizations' computer systems. Many organizations maintain data within their own computer systems in formats and in structures that are unique to their own businesses. As a result, when these computer systems interact with other organizations' computer systems, problems arise due to incompatibility.
Incompatibility may be caused by using incompatible data elements. For example, one system may define a particular data element as alphanumeric, i.e., capable of representing alphabetic or numeric values, while a second system may define the same data element as numeric only. Thus, if the first system transmits the data element with an alphabetic value to the second system, the second system will reject the data element because the data element is not numeric. As a result, the systems are unable to communicate with each other and become incompatible because of incompatible data elements.
In addition to incompatible data elements, the format of files in a computer system may also lead to incompatibility. More computer systems are being developed using newer technology, such as relational databases. On the other hand, many mainframe-based computer systems built in the past, known as legacy systems, use flat files or multi-value files (a type of flat file) rather than relational databases. This disparity in file format leads to incompatibility problems. For example, one file in a computer system may be stored as a relational database, while similar or necessary information may be stored as a flat file in a second computer system. If the first computer system attempts to access (i.e., view and update) the flat file in the second computer system using commands designed for relational databases, such as structured query language (SQL) commands, the second system will reject the attempt because the flat file cannot be accessed using relational commands. The same problem occurs regardless of the type of file structures used in the respective systems, and may also occur in electronic communication involving more than two systems. Thus, the systems are unable to communicate with each other because of incompatible file formats.
Another problem that arises when computer systems exchange information with each other is the possibility of breaches in the security of the computer systems. When a computer system can be accessed by external entities, such as other computer systems, it is vulnerable to security breaches, including data corruption and infection by computer viruses. Thus, there is a need to be able to exchange information among computer systems while maintaining the security of the computer systems.
As the number of entities exchanging information increases, so does the number of different computer systems using different data formats and different file formats. Accordingly, one computer system may be unable to communicate with another computer system due to incompatible data and/or file formats. Thus, there is a need for compatibility among different computers systems, while ensuring the security of the computer systems.
More specifically, client applications have been developed that utilize various database formats to organize information. These systems use format-specific commands to request information from databases. For example, in a relational database, an SQL request extracts information efficiently and quickly. However, there is a problem with this approach. The client applications that utilize a given database format cannot access information from a target database utilizing an incompatible format. This, in turn, results in the need for the client applications or the databases, or both, to be extensively modified to allow communication. Hence, a frustrated need exists to allow client applications to access, such as by viewing and updating, other applications that may utilize incompatible target databases, with no modification of the client application or the target databases.

Performance path method and apparatus for exchanging data among systems using different data formats


A method of and apparatus to data encode and decode for improving the reliability of data that is compatible with a conventional error correction code (ECC) block format, a storage medium, a system to drive the storage medium, and a method of generating an extra parity ECC block, the data encoding method including generating N number of ECC blocks with respect to user data and generating at least one extra parity ECC block for the generated N number of ECC blocks.

1. Field of the Invention
Aspects of the present invention relate to data encoding and decoding, and more particularly, to a method and apparatus to data encode and decode based on an error correction code (ECC) block, a storage medium having recorded thereon a program to implement the method, and a system to drive the storage medium.
2. Description of the Related Art
A system to drive a storage medium, such as a hard disk, a digital versatile disc (DVD), a high definition DVD (HD-DVD), or a Blu-ray disc, performs error correction code (ECC) block-based error correction for burst errors (such as physical scratches or fingerprints on the storage medium) or random errors (such as dust) during data decoding.
However, the performance of ECC block-based error correction of a conventional system to drive a storage medium is defined according to the type of the storage medium. For example, if the storage medium is a DVD, consecutive errors of a length corresponding to about 16 rows (16×182+10 bytes) of an ECC block can be corrected. For a HD-DVD, consecutive errors of a length corresponding to about 32 rows (32×182+10 bytes) of an ECC block can be corrected. For a Blu-ray disc, consecutive errors of a length corresponding to 64 rows (155×64 bytes) of an ECC block can be corrected. The physical length of consecutive errors that can be corrected can be set differently according to a recording density of a storage medium. For example, consecutive errors of approximately 6 mm for a DVD, consecutive errors of approximately 6.4 mm for an HD-DVD, and consecutive errors of approximately 9 mm for a Blu-ray disc can be corrected.
However, as the number of times the storage medium is used increases, degradation of data recorded thereon may occur due to recording or reproducing power and dust, scratches, and fingerprints resulting from management conditions of the storage medium. As a result, the probability that conventional standardized ECC block-based error correction fails increases. In particular, a physical scratch on the surface of the storage medium causes irreparable damage to data recorded thereon, increasing the probability that conventional standardized ECC block-based error correction fails. In the case of a failure in conventional standardized ECC block-based error correction, the reliability of data reproduced from the storage medium driving system decreases.
In an ECC block-based data communication system, the length of consecutive errors included in data may exceed the length of consecutive errors that can be corrected using an ECC block according to a condition like transmission speed. In this case, ECC-block based error correction fails in data decoding, causing transmission data loss. As a result, the reliability of data reproduced from the data communication system decreases.

Method and apparatus to data encode and decode, storage medium having recorded thereon program to implement the method, and system to drive the storage medium


An excimer laser annealing apparatus with an optical system. The optical system includes a cylindrical concave lens (A), a cylindrical convex lens (B), a fly-eye lens (C) made of a cylindrical lens array provided in a lateral direction and a fly eye lens (D) made of a cylindrical lens array provided in a vertical direction. The laser light is changed from an initial gaussian distribution to a rectangular distribution by virtue of the fly-eye lenses. The laser beam then passes through cylindrical convex lenses (E and F) and is reflected by a mirror (G) and is focused on the specimen by a cylindrical lens (H). The homogenous rectangular beam created has a longer width than the specimen so that the specimen may only be moved along one direction.

1. Field of the Invention
The present invention relates to a highly reliable laser annealing process suited for use in mass production of semiconductor devices, which enables uniform annealing at high yield. More particularly, the present invention provides a laser annealing process of a deposited film whose crystallinity had been greatly impaired by the damage it had received through processes such as ion irradiation, ion implantation, and ion doping.
2. Prior Art
At present, methods of lowering of process temperatures in fabricating semiconductor devices are extensively studied. The reason for such an active research for low temperature processes owe partly to the need for fabricating semiconductor elements on an insulator substrate made of, e.g., glass. Laser annealing technology is regarded promising as the ultimate low temperature process.
However, conditions for laser annealing are not yet established because conventional laser annealing processes were each conducted independently under differing conditions which depend upon the apparatuses and the coating conditions chosen individually in each process. This has misled and has allowed many to think that the laser annealing technology fails to give results reliable and consistent enough to make the process practically feasible. An object of the present invention is to establish, for the first time, the conditions for a laser annealing process which yields highly reproducible results.

Laser processing apparatus having beam expander

Semiconductor Energy Laboratory Co., Ltd.


The invention relates to a method for controlling a turbocharger system (10) fluidly connected to an exhaust manifold (102) of a combustion engine (100) in a vehicle (800). The turbocharger system (10) comprises a turbocharger turbine (22) operable by exhaust gases from the exhaust manifold, and a tank (40) with pressurized gas. The tank is fluidly connectable to the turbocharger turbine. The method comprises the steps of: predicting the coming drive conditions of the vehicle, injecting pressurized gas from the tank to drive the turbocharger turbine such that the turbocharger turbine is at least partly driven by the pressurized gas, in response to the predicted drive conditions, and/or charging the tank with pressurized gas in response to the predicted drive conditions, wherein the predicted drive conditions are indicative of the need for injection of pressurized gas from the tank.

A turbocharger, or a turbo, is a turbine-driven forced induction device that increases the efficiency and power output of a combustion engine, by forcing extra gas into the combustion engine. The turbocharger typically comprises a turbocharger turbine and a turbocharger compressor, the latter being driven by the turbocharger turbine. The improvement for a turbo-equipped combustion engine compared to a combustion engine operating without a turbo is that the turbocharger compressor can deliver more air/gas, into the cylinders of the combustion engine. Consequently, more fuel can be burnt.
In U.S. Pat. No. 9,322,322 a turbocharger system comprising a tank for compressed gas and an exhaust manifold conduit in fluid communication with an inlet of the turbocharger. The tank is in fluid communication with the manifold conduit and is arranged to push compressed gas into the manifold conduit during a predetermined pulse duration time period for initial compressor spin up in the turbocharger. However, after usage of the pressurized gas, recharge time of the tank is needed for full effect. In situations where a relatively high amount of pressurized gas is desired, the time for recharging the tank may be a limiting factor.
Thus, there is still a need in the industry for further improvements relating to the management of pressurized gas for driving said turbocharger.

Method for controlling a turbocharger system of a combustion engine in a vehicle


A semiconductor device includes: a first gate insulating film formed on a first nMOS transistor region in a semiconductor substrate; a second gate insulating film formed on a first pMOS transistor region in the substrate; a third gate insulating film formed on a second nMOS transistor region in the substrate; and a fourth gate insulating film formed on a second pMOS transistor region in the substrate. The first through fourth gate insulating films contain nitrogen. Each of the third and fourth gate insulating films has a thickness smaller than that of each of the first and second gate insulating films. The first gate insulating film has a nitrogen concentration peak at the interface between the first gate insulating film and the substrate. Each of the second, third and fourth gate insulating films has a nitrogen concentration peak only near an associated one of gate electrodes respectively formed thereon.

The present invention relates to semiconductor devices and methods for fabricating the same, and particularly relates to gate insulating films for metal-oxide semiconductor (MOS) transistors and methods for fabricating the gate insulating films.
In a complementary MOS (CMOS) transistor, for example, among MOS transistors that are typical MOS-type devices, a transistors for high speed driving (hereinafter, also referred to as a high-speed transistor) required to have a relatively thin gate insulating film and a transistor for high breakdown voltage (hereinafter, also referred to as a high-breakdown-voltage transistor) used for input/output signals with relatively high voltages and required to have a relatively thick gate insulating film are formed on a single semiconductor substrate. The gate insulating film of the high-speed transistor needs to have a thickness of about 1 nm to about 3 nm and also imperatively needs to have high reliability in resistance to dielectric breakdown and a low leakage current property.
In CMOS transistors, a dual-gate structure in which boron (B) is used as a dopant for a p-type gate electrode of a p-transistor and phosphorus (P) is used as a dopant for an n-type gate electrode of an n-transistor has been adopted. In this case, B as a p-type dopant has a diffusion coefficient larger than that of P as an n-type dopant, so that B diffuses in a gate insulating film of a high-speed transistor to reach the channel region through processes such as heat treatment during and after formation of the transistor. Such diffusion of B is called "permeation" and greatly changes the threshold voltage of the transistor. In addition, this B permeation becomes more pronounced as the thickness of the gate insulating film is reduced. The B permeation is conspicuous especially when silicon dioxide (SiO2) is used for the gate insulating film. The reduction of thickness of the gate insulating film causes gate leakage current to increase. Specifically, when a SiO2 film with a thickness of 3 nm or less is used as a gate insulating film, direct tunnel current is dominant, resulting in especially noticeable increase of gate leakage current.
As described above, when a SiO2 film is used as a thin gate insulating film of a high-speed transistor, neither B permeation nor increase of gate leakage current is suppressed.
In view of this, oxynitride films (silicon oxynitride films) to which nitrogen is introduced have begun to be used as gate insulating films (see, Japanese Unexamined Patent Publication (Kokai) No. 2003-347423).
FIGS. 7A through 7D and FIGS. 8A through 8D are cross-sectional views illustrating respective process steps of a conventional method for fabricating a semiconductor device (a CMOS transistor) using thermal oxynitridation so as to introduce nitrogen into gate insulating films.
First, as shown in FIG. 7A, a semiconductor substrate 100 in which a first p-well 101, a first n-well 102, a second p-well 103 and a second n-well 104 are formed is subjected to thermal oxidation, thereby forming a first insulating film 106 on the wells 101 through 104. At this time, isolations 105 are provided between the wells 101 through 104 in the semiconductor substrate 100.
Next, as shown in FIG. 7B, a first photoresist film 107 is formed on a portion of the first insulating film 106 located on the first p-well 101 and the first n-well 102. Then, wet etching is performed using the first photoresist film 107 as a mask, thereby selectively removing a portion of the first insulating film 106 located on the second p-well 103 and the second n-well 104. In other words, the first insulating film 106 remains on the first p-well 101 and the first n-well 102.
Then, as shown in FIG. 7C, the semiconductor substrate 100 is subjected to heat treatment in an atmosphere containing nitrogen such as a nitrogen monoxide (NO) gas or a nitrous oxide (dinitrogen monoxide) (N2O) gas. Accordingly, a first gate insulating film 109 is formed on the first p-well 101 and the first n-well 102 out of the first insulating film 106. The first gate insulating film 109 includes a nitridation region 108 having a nitrogen concentration peak at the interface between the first gate insulating film 109 and the semiconductor substrate 100. In addition, a second gate insulating film 110 having a thickness smaller than that of the first gate insulating film 109 is formed on the second p-well 103 and the second n-well 104. As the first gate insulating film 109, the second gate insulating film 110 also includes a nitridation region 108 having a nitrogen concentration peak at the interface between the second gate insulating film 110 and the semiconductor substrate 100.
The nitridation regions are herein regions having relatively high nitrogen concentrations including nitrogen concentration peaks.
Then, as shown in FIG. 7D, a silicon film 111 is deposited over the semiconductor substrate 100 on which the first gate insulating film 109 and the second gate insulating film 110 are formed. Thereafter, as shown in FIG. 8A, a second photoresist film 112 is formed to cover portions of the silicon film 111 respectively located above the first n-well 102 and the second n-well 104. Subsequently, ions of an n-type dopant (impurity) are selectively implanted in portions of the silicon film 111 respectively located above the first p-well 101 and the second p-well 103 by using the second photoresist film 112 as a mask, thereby forming an n-type silicon film 113.
Thereafter, as shown in FIG. 8B, a third photoresist film 114 is formed to cover the portions of the silicon film 111 respectively located above the first p-well 101 and the second p-well 103. Then, ions of a p-type dopant are selectively implanted in the portions of the silicon film 111 respectively located above the first n-well 102 and the second n-well 104 by using the third photoresist film 114 as a mask, thereby forming a p-type silicon film 115.
Subsequently, as shown in FIG. 8C, the n-type silicon film 113 and the p-type silicon film 115 are patterned into gate electrode shapes, thereby forming n-type conductor parts (i.e., a first n-type gate electrode 116 and a second n-type gate electrode 118) out of the n-type silicon film above the first p-well 101 and the second p-well 103, respectively, and also forming p-type conductor parts (i.e., a first p-type gate electrode 117 and a second p-type gate electrode 119) out of the p-type silicon film above the first n-well 102 and the second n-well 104, respectively. The first gate insulating film 109 is interposed between each of the first n-type gate electrode 116 and the first p-type gate electrode 117 and the semiconductor substrate 100. The second gate insulating film 110 is interposed between each of the second n-type gate electrode 118 and the second p-type gate electrode 119 and the semiconductor substrate 100.
Then, as shown in FIG. 8D, source/drain regions 120 made of an n-type doped layer are formed at both sides of the first n-type gate electrode 116 in the first p-well 101 and at both sides of the second n-type gate electrode 118 in the second p-well 103. In addition, source/drain regions 121 made of a p-type doped layer are formed at both sides of the first p-type gate electrode 117 in the first n-well 102 and at both sides of the second p-type gate electrode 119 in the second n-well 104.
FIGS. 9A through 9D, FIGS. 10A through 10C and FIGS. 11A and 11B are cross-sectional views illustrating respective process steps of a conventional method for fabricating a semiconductor device (a CMOS transistor) using plasma nitridation so as to introduce nitrogen into gate insulating films.
First, as shown in FIG. 9A, a semiconductor substrate 200 in which a first p-well 201, a first n-well 202, a second p-well 203 and a second n-well 204 are formed is subjected to thermal oxidation, thereby forming a first insulating film 206 on the wells 201 through 204. At this time, isolations 205 are provided between the wells 201 through 204 in the semiconductor substrate 200.
Next, as shown in FIG. 9B, a first photoresist film 207 is formed on a portion of the first insulating film 206 located on the first p-well 201 and the first n-well 202. Then, wet etching is performed using the first photoresist film 207 as a mask, thereby selectively removing a portion of the first insulating film 206 located on the second p-well 203 and the second n-well 204. In other words, the first insulating film 206 remains on the first p-well 201 and the first n-well 202.
Then, as shown in FIG. 9C, the semiconductor substrate 200 is subjected to thermal oxidation, thereby forming a second insulating film 208 out of the first insulating film 206 on the first p-well 201 and the first n-well 202 and also forming a third insulating film 209 with a thickness smaller than that of the second insulating film 208 on the second p-well 203 and the second n-well 204.
Thereafter, as shown in FIG. 9D, the entire surfaces of the second insulating film 208 formed on the first p-well 201 and the first n-well 202 and the third insulating film 209 formed on the second p-well 203 and the second n-well 204 are exposed to nitrogen plasma. Accordingly, a first gate insulating film 211 is formed on the first p-well 201 and the first n-well 202 and a second gate insulating film 212 having a thickness smaller than that of the first gate insulating film 211 is also formed on the second p-well 203 and the second n-well 204. Each of the first gate insulating film 211 and the second gate insulating film 212 includes a nitridation region 210 having a nitrogen concentration peak at the surface of the first or second gate insulating film 211 or 212.
Subsequently, as shown in FIG. 10A, a silicon film 213 is deposited over the semiconductor substrate 200 on which the first gate insulating film 211 and the second gate insulating film 212 are formed. Thereafter, as shown in FIG. 10B, a second photoresist film 214 is formed to cover portions of the silicon film 213 respectively located above the first n-well 202 and the second n-well 204. Subsequently, ions of an n-type dopant are selectively implanted in portions of the silicon film 213 located above the first p-well 201 and the second p-well 203 by using the second photoresist film 214 as a mask, thereby forming an n-type silicon film 215.
Thereafter, as shown in FIG. 10C, a third photoresist film 216 is formed to cover portions of the silicon film 213 respectively located above the first p-well 201 and the second p-well 203. Then, ions of a p-type dopant are selectively implanted in portions of the silicon film 213 respectively located above the first n-well 202 and the second n-well 204 by using the third photoresist film 216 as a mask, thereby forming a p-type silicon film 217.
Subsequently, as shown in FIG. 11A, the n-type silicon film 215 and the p-type silicon film 217 are patterned into gate electrode shapes, thereby forming n-type conductor parts (i.e., a first n-type gate electrode 218 and a second n-type gate electrode 220) out of the n-type silicon film above the first p-well 201 and the second p-well 203, respectively, and also forming p-type conductor parts (i.e., a first p-type gate electrode 219 and a second p-type gate electrode 221) out of the p-type silicon film above the first n-well 202 and the second n-well 204, respectively. The first gate insulating film 211 is interposed between each of the first n-type gate electrode 218 and the first p-type gate electrode 219 and the semiconductor substrate 200. The second gate insulating film 212 is interposed between each of the second n-type gate electrode 220 and the second p-type gate electrode 221 and the semiconductor substrate 200.
Thereafter, as shown in FIG. 11B, source/drain regions 222 made of an n-type doped layer are formed at both sides of the first n-type gate electrode 218 in the first p-well 201 and at both sides of the second n-type gate electrode 220 in the second p-well 203. In addition, source/drain regions 223 made of a p-type doped layer are formed at both sides of the first p-type gate electrode 219 in the first n-well 202 and at both sides of the second p-type gate electrode 221 in the second n-well 204.

Semiconductor device and method for fabricating the same

Matsushita Electric Industrial Co., Ltd.


The present invention relates to an adaptive telephone interface for use in a telephone apparatus comprising a telephone terminal including signal amplifier means, and audio/input device. The telephone interface is disposable between the terminal and the audio/input device, and comprises a processor for generating a test signal and sending this to the terminal at a plurality of different amplitudes. The processor is further formed and arranged for monitoring signals returned from the terminal by means of sidetone coupling, so as to identify the test signal amplitude at which clipping of at least part of the test signal occurs, and consequentially adjusting the amplification by the interface of a signal received from the audio input device, before sending it on to the terminal so as to avoid substantially clipping thereof by the terminal signal amplifier means in use of the telephone apparatus.

It is an increasingly common requirement in communications to have increased flexibility and interchangeability between handsets and/or headsets and the telephone terminals to which they connect, i.e. to be able to connect an earphone/microphone combination or headset unit to a different telephone terminal. To ensure that a signal with a suitable amplitude is transmitted from the headset via the telephone terminal to the destination (which could be another telephone unit), the necessary degree of amplification or attenuation between the telephone terminal and headset needs to be determined. If the transmitted signal has too low an amplitude then it will be too weak to hear easily at the destination. However, if the transmitted signal has too high an amplitude then it will be distorted at the destination. The signal amplitude from the telephone terminal must be optimized so that the signal sent to the headset can be heard clearly at the destination without clipping or distortion of the signal due to overdriving of the terminal. Clipping occurs due to the saturation of the microphone input circuit to the telephone terminal amplifier.


A multi-layer ceramic module comprises a multi-layer ceramic substrate having an upper side and a lower side, at least one semiconductor chip mounted on the upper side of the substrate, a plurality of module pins projecting from the lower side of the substrate and at least one decoupling capacitor mounted on the lower side of the substrate between adjacent ones of the module pins.

1. Field of the Invention
The present invention generally relates to a multi-layer ceramic module which utilizes discrete components such as decoupling capacitors and more specifically to an improved structure which reduces inductance effects associated with decoupling capacitors and which increases the effectiveness of decoupling capacitors.
2. Description of the Related Art
Advances in very large scale integration (VLSI) technology and increases in integration densities have caused numerous problems with multi-layer ceramic modules which utilize external discrete components in close proximity to the chip. As the size of the die or chip increased from a few millimeters to tens of millimeters, the on chip and off chip power distribution problem requires better power supply decoupling. The problem is somewhat relieved, especially for high frequencies, by on chip decoupling. However, for intermediate and low frequency decoupling one still needs to provide external decoupling capacitors as close as possible to the chip.
The conventional method of decoupling a module, or Temporary Chip Attach (TCA) substrate, is shown in FIG. 1. The decoupling capacitors 10 are typically placed on the top surface 11 of the MLC substrate 12 surrounding the chip 13 and are connected to internal MLC power and ground distribution planes. This method was conventionally adequate when the chips were relatively small in size and required low power, but with present day chips the distance from the edge of the chip to the center of the chip introduces significant distributed inductance which makes external decoupling highly ineffective.
In addition to power decoupling, it is often required to add external components to the MLC package in close proximity to the chip input/output. Such external components may consist of discrete passive RLCs or active chiplets with analog or digital functions. These external components are typically difficult to integrate in the integrated circuit and require low inductance, resistance, and cross coupling paths to the chip.
Furthermore, MLC substrates are often used as space transformers in state-of-the-art VLSI wafer test systems. The substrate is used in a "reverse" manner such that the pins of the module substrate interface with the test system's pin electronics test head, while the chip is replaced with the wafer contacting probe. One of the new probing approaches is to use Thin Film Interface (TFI) probes or membrane probes. However, a problem occurs because physically adapting these TFI probes to a MLC space transformer with decoupling capacitors on the periphery of the target area becomes somewhat difficult and costly.
The general problem of module package power supply decoupling is a well known problem and has been address before with a variety of configurations for different packages. However, none of the conventional solutions specifically address the problems of increasing chip size and TFI interfacing, described above.

Multi-layer ceramic substrate decoupling

International Business Machines Corporation


A flow path includes a return bend portion which guides a working fluid to an inside in the radial direction by reversing the working fluid discharged to an outside in a radial direction from an upstream-side impeller, and a guiding flow path which is connected to a downstream side of the return bend portion and leads the working fluid to the inside in the radial direction so as to guide the working fluid to the downstream-side impeller. In a return vane which is provided in the guiding flow path, a trailing edge is formed such that a second end portion on a second side in an axial direction is positioned closer to an inside in a radial direction than a first end portion on a first side in the axial direction.

A rotary machine such as a centrifugal compressor mainly includes an impeller which rotates around an axis and a casing which covers an outer peripheral side of the impeller to form a flow path of a working fluid between the impeller and the casing.
In a multi-stage rotary machine including a plurality of stages of impeller in an axial direction, a flow path of each stage includes a diffuser flow path, a return bend portion, and a guiding flow path. The diffuser flow path is provided on a radially outer side of the impeller, extends radially outward of the axis from the impeller, and leads a working fluid, which is discharged from an outlet of the impeller, radially outward. The return bend portion is continuously provided to a radially outer side of the diffuser flow path and reveres a flow direction of the working fluid from a radially outer side to a radially inner side. The guiding flow path is provided on a downstream side of the return bend portion and leads the working fluid to an inlet of a subsequent stage impeller. The working fluid discharged from the outlet of the impeller has a component in a turning direction due to a rotation of the impeller around the axis. If the working fluid reaches the subsequent stage impeller via the diffuser flow path, the return bend portion, and the guiding flow path in a state where a turning component remains in the working fluid, it adversely affects compression processing for the working fluid in the subsequent stage impeller, and thus, efficiency of the rotary machine may decrease.
PTLs 1 and 2 disclose a configuration including a return vane (guide vane, vane) in the guiding flow path for a purpose of rectification. The return vane is provided in the guiding flow path, and thus, a component in a turning direction of a working fluid which is discharged from an outlet of an impeller and has passed through a diffuser flow path and a return bend is removed, and a reduction in efficiency of a rotary machine is suppressed.

MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION


For generating a three-dimensional magnetic resonance image of a respirating examination subject, the respiration of the examination subject is divided into a number of predefined clusters. Based on a measured respiratory position of the examination subject, one of these clusters is selected. The scanned k-space range is divided into a number of data acquisition shots which, by means of a particular k-space trajectory, each fill a number of k-space lines. The different shots are acquired for the different clusters until all shots of the measurement data set are assigned together to at least two adjacent clusters. The magnetic resonance image is reconstructed from those shots that are assigned to at least two adjacent clusters.

1. Field of the Invention
A method for acquiring a measurement data set of a respiring examination subject, using magnetic resonance technology, a magnetic resonance device, computer programs, as well as electronically readable data media.
The invention relates to a method for the acquisition of a measurement data set of an examination subject by means of magnetic resonance technology, a magnetic resonance system, a computer program as well as an electronically readable data medium.
2. Description of the Prior Art
Magnetic resonance (MR) is a known technology with which images from the interior of an examination subject can be generated. Expressed simply, the examination subject is placed in a magnetic resonance imaging scanner, in a strong, static, homogenous base magnetic field, also called a B0 field, having a field strength of 0.2 tesla —7 tesla and more, such that the nuclear spins of the subject orient themselves along the base magnetic field. In order to trigger magnetic resonance signals, the examination subject is irradiated with radio frequency excitation pulses (RF pulses), the triggered magnetic resonance signals are detected and entered into a memory that represents a mathematical domain known as k-space, and MR images are reconstructed on the basis of the k-space data, or spectroscopy data are determined. For the spatial encoding of the measurement data, rapidly activated magnetic gradient fields are superimposed on the base magnetic field. The recorded measurement data are digitized and stored as complex number values in a k-space matrix. From the k-space matrix populated with data values in this manner, an associated MR image can be reconstructed, for example, by means of a multi-dimensional Fourier transformation.
The respiratory movement of a patient that is to be examined by means of MR can lead to so-called ghosting, to blurring, and/or to intensity losses in the images generated, as well as registration errors between generated images particularly in an examination of the organs of the thorax and the abdomen, i.e. of examination regions affected by respiratory movement. These artifacts can make it difficult for a physician to perform an analysis on the basis of the images, and can lead to lesions being overlooked, for example. Numerous techniques exist in the prior art for reducing artifacts resulting from respiratory movement. One of these techniques is respiratory gating. Respiratory gating is a technique with which, during the MR measurement, the respiration of the patient is recorded and assigned to the acquired measurement data. With respiratory gating, only measurement data are then used for reconstruction for which the associated recorded respiratory movement fulfills certain specifiable criteria.
The patient's respiration can be detected thereby with external sensors such as, for example, a pneumatic cushion or with MR signals, so-called navigators. A navigator is usually a short sequence which acquires MR signals, for example, from the diaphragm or another signal source in the examination subject, whose movement is correlated with the patient's respiration. Via the position of the diaphragm, or other signal source, the respiratory motion can be tracked.
With respiratory gating with navigators, the navigator sequence is interlaced for example with the imaging sequence and a diaphragm position measured with a navigator is then assigned immediately thereafter (or before) to the acquired imaging data.
A distinction is made between retrospective and prospective respiratory gating.
With retrospective respiratory gating the respiratory movement is detected and recorded during the MR measurement, but not evaluated. Instead, the k-space that is to be recorded is measured repeatedly. For the reconstruction, only a portion of the measured data are referenced, preferably that data in which the respiratory signal lies within a specific window for a distinctive respiratory position. If a specific k-space data point that is necessary for the image reconstruction is repeatedly measured within the distinctive window, then the data can be averaged. If, instead, a data point is always measured outside of the window, then that data point deviating the least from the distinctive position can be used for the reconstruction.
With prospective respiratory gating, the physiological respiratory signal measured using a respiratory sensor (e.g. the diaphragm position measured with a navigator sequence) is evaluated during the measurement, and the MR measurement is controlled, based on the recorded physiological signal. In the simplest embodiment, the so-called acceptance/rejection algorithm (ARA), the measurement of an imaging data packet (and if applicable, the associated navigator sequence) is repeated until the physiological signal falls within a previously defined acceptance window.
One example of an acceptance/rejection algorithm of this type and, at the same time, the first description of respiratory gating with navigators, is described in the article by Todd S. Sachs, Craig H. Meyer, Bob S. Hu, Jim Kohli, Dwight G. Nishimura and Albert Macovski: "Real-Time Motion Detection in Spiral MRI Using Navigators," MRM 32: Pages 639-645 (1994). The authors acquired one or more navigators for each excitation of a spiral sequence. The navigators were acquired here following the acquisition of the image data. Different navigators are distinguished by their spatial orientation. From each navigator, a spatial displacement along the axis of the navigator in relation to a reference navigator is calculated using a cross-correlation. The navigator scan acquired following the first imaging scan is used, in each case, as a reference. A specific imaging scan is repeated until the spatial displacement determined with the navigator, in relation to the reference, is less than a threshold value provided by a user. This, therefore, relates to an acceptance/rejection algorithm based on one or more spatial displacements.
Another example of an acceptance/rejection algorithm is described by Wang et al. in "Navigator-Echo-Based Real-Time Respiratory Gating and Triggering for Reduction of Respiratory Effects in Three-Dimensional Coronary MR Angiography," Radiology 198; Pages 55-60 (1996). In this case, the physiological signal is the displacement of the diaphragm position, determined with a navigator, in relation to a reference state. One difference from the work by Sachs et al. is that, in each case, a navigator is acquired before and after the imaging scan, and that the imaging scan is then only accepted if the displacement determined by means of both navigators is less than the threshold value.
In order to determine the acceptance window, a so-called pre-scan is normally carried out for each patient, in which the respiratory movement is recorded, for example, with the navigator sequence, but imaging data are not yet acquired.
Prospective respiratory gating is normally more efficient than retrospective respiratory gating. A prerequisite for prospective respiratory gating is a real-time capability of the normally-provided control software for the MR apparatus. For this purpose, real-time capability means that data measured with the sequence (in this case, the sequence comprises imaging and navigator sequences) can be evaluated during the sequencing, and the further course of the sequencing can be influenced by the results of this evaluation, wherein the time period between recording the data and influencing the further course is short in comparison with the typical time constants of the respiratory movement (in this case, particularly, the respiratory cycle of a human being, which amounts to between 3 and 10 seconds).
The main problem with the acceptance/rejection algorithm is that the respiration of the patient frequently varies during the examination. The variations in the respiratory movement can be, thereby, such that the respiratory positions within the once specified acceptance window are rarely, or no longer, detected. This leads to extended acquisition periods and can even lead to the measurement not being completed at all in the normal manner.
A large number of alternative prospective gating algorithms exist, which either attempt to improve the efficiency with respect to the acceptance/rejection algorithm, or to make the measurements more robust, for the case that the respiration during the measurement varies or drifts. Common to all of this is that—as long as the respiration is recorded with a navigator—the prospective decision is based solely on the last measured respiration position (e.g. the last measured diaphragm position or the last measured diaphragm positions).
The most important algorithm, by far, that addresses this problem is "Phase Ordering With Automatic Window Selection" (PAWS), which is described, for example, in the article by P. Jhooti, P. D. Gatehouse, J. Keegan, N. H. Bunce, A. M. Taylor, and D. N. Firmin, "Phase Ordering With Automatic Window Selection (PAWS): A Novel Motion-Resistant Technique for 3D Coronary Imaging," Magnetic Resonance in Medicine 43, Pages 470-480 (2000) and in the U.S. Pat. No. 7,039,451 B1. PAWS finds a final acceptance window during the runtime, and can thus react in a flexible manner to a changing respiration. A further goal of PAWS is to ensure a certain degree of "phase-encode ordering" (or in short, "phase ordering"). This means that adjacent lines in the k-space are acquired in similar respiration states. In particular, a variation in the respiratory state during acquisitions in the vicinity of the k-space center, which is particularly sensitive to movement, is to be avoided. PAWS was developed for a 3D Cartesian acquisition technique. The ky-kz array system used for this acquires a complete kx-kz plane of the 3-dimensional k-space following each navigator. The modulation of the k-space signal along the kz axis resulting from the transcendental state after interrupting the stationary steady state by the navigator (as well as potential activated preparation pulses, or the waiting for a further physiological signal, such as an EKG trigger) on the kx-kz plane, is therefore smooth. Discontinuations may arise in the ky axis as a result of residual movement, which can be manifested in the image as artifacts and blurring along the first phase encoding axis ky. This does not only apply when the segment border exists in the vicinity of the k-space center. Peristaltic movements, as well, which are not detected by the respiratory sensor, can lead to artifacts in the images.
PAWS exists in different so-called "bin" variations. In PAWS, the width of the final acceptance window is determined. The respiratory positions encompassed by this acceptance window are found automatically during the runtime, in contrast to acceptance/rejection algorithms. The filling of k-space occurs in clusters. A cluster (in the original work, the term "bin" is used instead of "cluster") is characterized by a respiratory position range, an acceptance range, and comprises all k-space lines that have already been measured, after which a respiratory position in the respiratory position range assigned to the cluster is measured. In the n-bin variation of PAWS a respiratory position range is covered by n successive clusters, the width of which range is the same as the acceptance window.
Furthermore, a starting position in the k-space is assigned to each cluster, wherein the number of different starting positions is n. Different starting positions are assigned to clusters with adjacent respiratory positions where n>1. As soon as a respiratory position assigned to a cluster is measured with the navigator, the measurement of a k-space line that has not yet been measured within said cluster is initiated. The decision regarding which k-space lines still to be measured are selected takes into consideration, as a whole, the already acquired k-space lines of adjacent clusters as well. By way of example, a still missing k-space line is selected such that an arbitrary group of n adjacent clusters is complete to the greatest degree possible, wherein the arbitrary group of n adjacent clusters contains the cluster to which the current measured respiratory position is assigned; i.e. the group of n adjacent clusters comprising the largest possible number of different k-space lines. As soon as an arbitrary group of n adjacent clusters comprises all of the k-space lines that are to be measured, the measurement is stopped, because the overall variation in the respiratory position is limited in these measurement data, thereby, to the acceptance window.
The n different starting points and clusters of the n-bin variation of PAWS normally result in n segments in the k-space. For this, each segment consists of adjacent k-space lines. The variations to the respiratory positions within a segment measured with the navigator correspond to the position range assigned to a cluster (in the original work, the term "bin size" is used), and thus one nth of the acquisition window. The variation to the respiratory position is greater over the course of the entire k-space, and has an upper limit as a result of the specified acceptance window. The lines belonging to the same segment are measured during similar respiratory states. Thus, the modulation of the signal changes with the respiration at the segment borders. As a result, position jumps occur at the segment borders. An aim of the different bin-variations of PAWS is to displace the segment borders away from the movement sensitive k-space center. Another aim is to obtain a greater degree of efficiency.
In the previously mentioned article by Jhooti et al., as well as in the follow-up work by P. Jhooti, P. Gatehouse J. Keegan, A. Stemmer, D. Firmin: "Phase ordering with Automatic Window Selection (PAWS) with Half Fourier for Increased Scan Efficiency and Image Quality;" Proc. Intl. Soc. Mag. Reson. Med. 11 (2004); Page 2146, the 1-bin, 2-bin, 3-bin, and 4-bin variations are compared with one another. The result of this comparison shows that the 1-bin and the 2-bin variations of PAWS are the most efficient, i.e. for a given width of the acceptance window, the measurements are completed most quickly. The 1-bin variation is discarded because it does not allow for "phase ordering," the 4-bin variation (and higher) is discarded due to lower efficiency. The 3-bin variation is less efficient than the 2-bin variation. The reason for this is the unidirectional growth direction of the cluster with starting positions at the left and right k-space edges. As soon as the gap between one of these peripheral clusters and the central cluster (with a starting position in the k-space center, and a bidirectional growth direction) is closed, then said clusters continue to grow until the gap between the other peripheral clusters and the central cluster is closed, as soon as a respiratory position is measured that is assigned to the first peripheral cluster. This normally leads to multiple k-space lines acquired at the cluster borders (segment borders). This problem does not exist with the 2-bin variation. In this variation, every second cluster grows in a unidirectional manner from the left-hand k-space edge, through the k-space center, toward the right-hand k-space edge, and the remaining clusters grow in a unidirectional manner from the right-hand k-space edge, through the k-space center, toward the left-hand k-space edge. The measurement is complete as soon as two adjacent clusters (with opposite growth directions) "meet." However, with a symmetrical scanning of the k-space, as is the case with the 2-bin variation, the cluster border frequently lies in the vicinity of the k-space center, which is particularly sensitive to movement, which may lead to strong image artifacts. The probability of cluster borders lying in the vicinity of the k-space center is substantially lower with the use of partial Fourier (i.e. an asymmetric scanning of the k-space).
Of practical relevance, therefore, are the so-called 2-bin and 3-bin versions of PAWS, wherein, with symmetrical scanning, the 3-bin variation is preferred, and with asymmetric scanning, the 2-bin variation is preferred. This analysis is based on a 2-bin variation, in which the starting position alternates between the left-hand and right-hand k-space edges of adjacent clusters. Accordingly, the clusters grow, respectively, from the starting positions assigned thereto, firstly toward the k-space center.
It should also be noted that in some works, only a single respiratory position is assigned to a cluster. The width of the final acceptance window then amounts to n times the resolution of the respiratory signal. In this alternative formulation, one obtains a flexible selection of the acceptance window in that one first enlarges the respiratory position measured with the sensor, such that the n adjacent resulting respiratory positions cover a respiratory range corresponding to the width of the acceptance window.
PAWS was originally developed for a ky-kz array system, with which, in each case after recording the respiratory signal, all k-space lines are acquired with a specific value of the second phase-encoding gradient (in the kz axis). Accordingly, the "phase-ordering" is also limited to a Cartesian k-space axis, which can lead to a higher occurrence of residual movement artifacts in this axis.
Another prospective gating algorithm, which addresses the problem of a varying respiration, is the Diminishing Variance Algorithm (DVA) (Todd S. Sachs, Craig H. Meyer, Pablo Irarrazabal, Bob S. Hu, Dwight G. Nishimura: "The Diminishing Variance Algorithm for Real-Time Reduction of Motion Artifacts in MRI;" MRM 34; Pages 412-422 (1995)). First, in an initial phase, the k-space that is to be acquired is completely recorded, without gating, and for each acquisition period, the displacement of the respiration position in relation to a reference position is measured with a navigator, and recorded. At the end of the initial phase, the most frequent respiratory position is determined using a histogram, and designated as the mode for the statistical distribution. The k-space data, the stored respiratory positions of which deviate the most from the mode, are then re-acquired together with the navigator, and the histogram (and thereby the mode) is updated. This re-acquisition of the k-space data, which in each case deviate the most from the current mode, is continued until all of the respiratory positions lie within an acceptance window of a given width, or a time limit has been reached.

Magnetic resonance method and apparatus for obtaining a set of measured data relating to a breathing object of interest


Methods and apparatuses are described for generating and manipulating 3D objects in a 3D environment of an alternative reality software application. A server retrieves a data set comprising data elements, each having one or more attributes. The server generates, for each data element, a virtual object, each virtual object positioned inside a virtual container and located in proximity to a center of the virtual container. The server attaches virtual magnets to an exterior surface of the virtual container, each magnet associated with a data filter value and an attraction value. The server determines, for each virtual object, a movement distance and a movement speed in relation to each virtual magnet based upon the data filter value and the attraction value for the virtual magnet. The server moves at least a portion of the virtual objects to a new location based upon the movement distance and movement speed.

Generally, alternative reality software applications provide for an experience in which a user's real-world viewing perspective is replaced by or enhanced with a virtual 3D environment. In the context of this application, the term "alternative reality" encompasses all different types of virtual experiences, including but not limited to: virtual reality (VR), augmented reality (AR), mixed reality (MR), extended reality (XR) and others. A user wears a headset or similar apparatus that includes specialized display devices to render the virtual environment to the user, and the headset can include certain components (e.g., gyroscope(s), accelerometer(s), magnetometer(s), etc.) that detect and capture the user's head movements in order to update the virtual environment in response to the movements in a seamless, real-time manner. Exemplary headsets comprise the VIVE™ and VIVE Pro™ available from HTC Corporation, the Oculus Rift™ available from Facebook Technologies, LLC, and the Sony Playstation™ VR headset available from Sony Corporation.
An emerging type of software application being used in alternative reality environments is data exploration, where data repositories can be leveraged to generate 3D objects in the alternative reality environment that correspond to data points within one or more databases. A user of the alternative reality software application can view and manipulate the 3D objects in order to analyze and investigate the underlying data points in an immersive and interactive fashion. However, most alternative reality software applications fail to provide functionality that enables a user to efficiently interact with and explore large volumes of data points, particularly when the data points are closely clustered in the 3D virtual environment. In addition, such alternative reality software application do not allow for manipulation of data points in relation to one or more external data interaction objects that can be placed in the 3D environment in order to move and/or rearrange the 3D objects representing the data points—including control of movement playback over time to see how 3D objects change and move as the data interaction objects are controlled by the user.

Generating and manipulating three-dimensional (3D) objects in a 3D environment of an alternative reality software application


The invention consists of a liquid end for a plunger pump, having vertical inlet and outlet, with the suction and discharge valves readily accessible for maintenance without disturbing the suction and discharge piping. The liquid end also includes a relief valve which is accessible without disturbing suction or discharge piping. The passages to and from the relief valve are internal to the housing. Inserts are provided in the valves to eliminate dead space and to facilitate the removal of any trapped air which might adversely affect the performance of the pump.

Plunger pumps have been used for a wide variety of metering applications, particularly those involving low flow rates. The volumetric delivery of such pumps can be affected by various factors. The presumed volume delivered by such pumps is calculated based on the displacement per revolution. However, if the cylinder does not fill completely and efficiently during the intake stroke, the precise amount delivered is not capable of accurate measurement.
Some liquids are so viscous that a booster force must be applied to the liquid in its storage container in order to move the material through the suction lines and into the cylinder.
Due to the wide variety of liquids that are pumped through plunger pumps, further inaccuracies can result if the material has varying physical properties with temperature, which may affect its viscosity, and if the material is compressible to any degree.
Dead spots are particularly undesirable in the construction of plunger pumps since vapors such as air may accumulate in those dead spots which, depending upon the volume, may prevent the pump from pumping at all. In some designs, the dead volume substantially exceeds the total displacement volume and this can prevent the pump from purging itself while it is operating.
Frequently, when it is time to maintain such pumps, the piping must be disconnected from the pump body so that work can commence on renewing or replacing the check valves. The check valves are a part that requires more frequent maintenance among the various pump parts. Several known designs incorporate the check valves in a manner that requires disassembly of the suction and discharge piping to obtain access for maintenance. Typical of such plunger pump designs are U.S. Pat. Nos. 3,801,234; 4,854,835; 4,269,572. Other references address the issue of the need to remove the valves easily but provide fairly complicated solutions for their removal. Such patents include U.S. Pat. No. 4,618,316. Yet other designs feature complicated internal passages among various cylinders, such as U.S. Pat. No. 3,746,476. Yet other designs still require disassembly of the suction and/or discharge piping for full and ready access to the complete suction and/or discharge valve assemblies or for maintenance of the relief valve. Typical of such patents are U.S. Pat. Nos. 4,477,237 and 4,778,347.
The apparatus of the present invention seeks to provide a design for a plunger pump wherein the suction and discharge valves are easily accessible without disassembly of piping. The design further seeks to embody a built-in relief valve which is easily accessible without removal of any piping and which is fully internally ported from the discharge piping to the suction piping. The design further seeks to eliminate as much as possible any dead spots and to provide a means for elimination of air which may be trapped in such dead spots which could possibly prevent the pump from pumping.


Device including an input rectifying circuit 2 for effecting a full wave rectification on an AC input, and an output converter which includes a transforming device 11 having a primary winding 11a and a secondary winding 11b, the primary winding being connected through an inductor 16 with paired outputs of the input rectifying circuit, the secondary winding being connected through an output rectifying circuit with a load. Switching element 18 is controlled by a control circuit 20 to operate between ON and OFF states, and capacitor 19 is connected with the input rectifying circuit and the transforming device so as to be charged during the OFF state period of the switching element 18 through a charging circuit including the inductor 16, and to discharge during the ON state period through the primary winding 11a of the transforming device 11. The control circuit 20 controls the switching element to operate in an ON-OFF manner with a frequency faster than the frequency of the AC input. A second switching element 31 is connected in series with the inductor 16 to paired outputs of the input rectifying circuit 2 and through a diode 17 with a capacitor charging circuit. An interrupting device renders the second switching element non-conductive when the current through the second switching element exceeds a predetermined value.

The present invention relates to a DC power device adapted for receiving AC input and generating DC output. More specifically, the present invention relates to a switching type electric power device wherein an input from a rectifying circuit, which is adapted for rectifying AC input, is subjected by a switching element to ON-OFF control and then to a voltage increase or decrease by a transforming device, and thereafter converted into DC power by another rectifying circuit. The present invention further relates to a power factor correction control device which is adapted for use in a power device for correcting the power factor.
A switching type electric power device of the type described above includes an input rectifying circuit having diodes connected to form a bridge circuit, the output of the rectifying circuit is connected to an input capacitor. The output of the input rectifying circuit is connected to a primary winding of an output converter having a transforming device which is adapted for increasing or decreasing the output voltage of the input rectifying circuit. A switching element is provided for subjecting the output of the input rectifying circuit, which is connected with the primary winding of the converter, to an ON-OFF control. The transforming device of the output converter has a secondary winding which is connected through an output rectifying circuit to a load.
In a circuit provided with such an input capacitor, input current flows only during a period wherein the input capacitor is being charged, and the current is interrupted during a period wherein the input voltage is below the voltage of the input capacitor. Therefore, even when the AC input voltage is of a sinusoidal shape, the current wave form assumes a steep shape resulting in a decrease in power factor and producing harmonic components.
It has been realized and recognized as a problem that when a commercial electric power source is utilized as the AC input power source the harmonic components produced in the switching power device are allowed to flow into the commercial power source lines to thereby distort the commercial power source. Thus, in recent years, a problem in the field of the switching power device has been to take into account this tendency and to suppress the generation of such harmonic components.
In order to solve the problem, there has been proposed to provide a power device which utilizes a rectifying circuit of a type called DITHER system wherein an AC input is subjected by means of a switching element to ON-OFF control. A typical example of a switching type power device utilizing a DITHER type rectifying circuit is the one which is described as the voltage raising circuit example 1 described in the article "Application of a DITHER Rectifying Circuit to a Switching Type Power Device" by Isao TAKAHASHI in the text for a seminar entitled "Power factor correction Circuit for Switching Type Power Device" held by the Japan Industrial Technology Center on Nov. 26 and 27, 1992.
In the known circuit, the input rectifying circuit adapted to receive AC power as an input has one of output connected through an inductor and a diode with one end of a primary winding of the transforming device, the other end of the primary winding being connected through a switching element with the other of the outputs of the input rectifying circuit. A capacitor is connected in parallel with the primary winding of the transforming device and the switching element. A point between the inductor and the diode is connected through a second diode with a point between the primary winding and the switching element. The switching element is actuated by means of a control circuit to conduct ON-OFF operation with a frequency faster than the frequency of the AC input whereby current proportional to the input voltage is allowed to flow into the capacitor during the ON period of the switching element resulting in an improvement of power factor and suppression of harmonic components.
The Japanese Laid-Open Patent Nos. Hei 3-207268 and Hei 4-127875 also disclose switching type power devices which utilize a similar DITHER type rectifying circuit.
It has been recognized that the switching type power device utilizing the aforementioned DITHER type rectifying circuit is advantageous in that a high power factor can be obtained and harmonic components can be suppressed with a circuit of a relatively simple structure. It should however be noted that the circuit of this type has a disadvantage in that the capacitor voltage changes to a significant degree depending on variations in the input voltage and the load. It has therefore been required in order to accommodate for wide ranges of variations in the input voltage and the load to vary the frequency of the control circuit for providing the ON-OFF control of the switching element in accordance with the changes in the input voltage and the load so that the variations in the capacitor voltage can be minimized. It should however be noted that making the frequency of the control circuit variable as described will make it necessary to have the transforming device, the inductor and the input and output filters of larger capacities which lead to a difficulty in control.

Electric power device with improved power factor


By forming, after the annealing of the continuously cast body, a limited number of precipitates apt to the control of the grain growth, and utilising a cold rolling reduction ratio of at least 70%, it is possible to obtain in a subsequent step of continuous nitriding the direct formation of nitrides useful for the grain growth control and subsequently, still in a continuous treatment, to at least start the oriented secondary recrystallization.

The present invention refers to a process for controlling and guiding the secondary recrystallization in the production of grain oriented electrical steel strips and, more precisely, to a process in which during a continuous treatment after primary recrystallization it is possible to complete, or at least to start, the oriented secondary recrystallization.
It is known that, in the grain oriented electrical steel strips, the desired final magnetic characteristics are obtained through a complex series of interdependent transformations of the strip structure, which occur during a final treatment of secondary recrystallization. This step, here understood as the one in which the grains having Miller index  less than 001 greater than  (110) develop with higher velocity, was up to now obtained during an extremely long annealing treatment at high temperature in static annealing furnaces (box annealing) in which tightly wound cold coils of the strip having the desired final thickness are introduced, having a weight typically comprised between 6 and 18 tons, which coils are annealed, cooled and then discharged. This static annealing also eliminates from the strip elements which would impair its final quality and forms on the strip surface a coating, called xe2x80x9cglass filmxe2x80x9d, useful to electrically insulate the strip and to act as a substrate for further necessary coatings.
This box annealing, however, has some major disadvantages, among which the long duration of the treatment, requiring some days, and the fact that a single batch comprises a plurality of coils. Those coils, due to the high treatment temperatures and times, are deformed under their own weight, which makes it necessary to eliminate the deformed zones through a slitting operation. More scrap is produced due to sticking of adjacent coil spires, which occurs even if oxide powder annealing separators are utilised. Still more scrap is due to quality problems (deriving both from damages attributed to the handling of coils during loading and unloading of box annealing furnaces and from different treatment conditions experienced by the most external and the most internal spires of the coils during the slow annealing process) which call for the elimination of the initial and final spires of the coils. Moreover, the process imparts to the strips the form due to coiling, which strips will have to be further treated to bring them back to a flat shape, necessary for the manufacture of the final products, usually transformers cores.
Further disadvantages, deriving from the box annealing utilised for the metallurgical final treatment of the grain oriented strips, relates to the process control.
In fact, while on one hand the high temperature purification of the strip, substantially obtained through solid phase extraction of elements such as sulphur and nitrogen by interaction with the annealing atmosphere, is not critically influenced by the atmosphere and temperature differences along the coiled strip (longitudinal and transversal gradients), on the other hand the grain growth and oriented secondary recrystallization are greatly influenced by such differences. In fact, due to the microscopic scale of such metallurgical processes and to the peculiarities of the oriented secondary recrystallization, the course of the process is critically controlled by the physical and chemical xe2x80x9cmicro-environmentxe2x80x9d in which the different parts of the strip are.
To better clarify the importance of the process control during the final metallurgical annealing as well as the relevant difficulties linked to a static thermal treatment, some details will hereinafter be exposed with reference to the state of the art and to the physical and chemical phenomena occurring during the treatment. The final result of the oriented secondary recrystallization is a polycrystalline structure iso-oriented along the crystallographic direction of easier magnetisation ( less than 100 greater than  according to the convention of the Miller indexes), with an angular dispersion, for a good industrial product, lesser than 100. This is obtained through a delicate process which selects for the growth only crystals already having the above orientation, such crystals representing, before the final annealing, a very small fraction of the starting microstructure. In this process, a dimensional change occurs in the product structure which varies from some micrometers before the annealing to some millimeters after.
The desired result of this process, difficult to obtain at industrial scale, strongly depends on the treatment conditions preceding the final annealing and determining geometry, the superficial state and the microstructure of the strip. As already mentioned, this result is obtained during the final metallurgical annealing in a way critically controlled by the evolution kinetics of the dimensions of some. particles such as sulphides and nitrides present in the metallic matrix and by the diffusion of relevant composing elements between the same particles as well as towards the strip surface, and through the latter towards both the exterior and the interior of the metal matrix. The last two phenomena are controlled by interaction with the annealing atmosphere (micro-environment).
Even small variations in the kinetics of said processes (as well as of the temperatures at which the same are activated and developed) in different zones of the strip depending on different micro-environments produced during the box annealing, bring to differences in the development of the grain growth, which in the best case mean final grain dimensions and orientation different from zone to zone, entailing variations of the magnetic characteristics along the strip and in the transverse direction.
In more critical cases, which however are not so rare in the industrial practice, such differences lead to a loss of control in the oriented secondary recrystallization, with totally inadequate magnetic characteristics in part of the final product, which must thus be further conditioned at the end of the production cycle, or downgraded or scrapped.
For analogous reasons the chemical reactions at the surface depend on the micro-environment: for instance, the superficial oxidation layer evolution with time and during the thermal treatment strongly influences the exchange reaction between the metal matrix and the annealing atmosphere, further complicating the already delicate aspects of the metallurgical process control.
The differences between the different superficial reactions induced by the different micro-environments depending on the coil geometry (head and tail of the strip, external layers and core of the coil, and so on) more directly lead to differences in morphology and composition of the superficial layer of the strips.
The superficial characteristics are another important aspect of the grain oriented strips, in that they directly or indirectly influence the magnetic and insulation characteristics thereof. Thus, variations of the superficial quality along the strip constitute an industrial problem of product quality and hence of process control. It is clear now that the box annealing of grain oriented electrical steel strips having the final thickness, utilised to start and develop the oriented secondary recrystallization, as well as to modify surface structure and morphology and to purify the matrix of some elements not desired in the final product, is a treatment technique for some aspects inconvenient and expensive, in that requires a large number of plants to sustain an adequate production capacity, has a low productivity, physical yields difficult to control, and above all do not allows to perform a process control absolutely necessary for such a complicated production and which is present in all the other production steps, form the steel shop production to the primary recrystallization.
As already said, the secondary recrystallization process consists, in this kind of products, in the selective growth of some grains having a specific orientation with respect to the rolling direction and the strip surface. Trough a complex process, well known to the experts, it is possible to let grow mainly the desired grains, utilising the so called grain-growth inhibitors, i.e. non-oxide precipitates (sulphides, selenides, nitrides) which interact with the grain boundaries impairing and/or preventing the movement thereof (and thus the grain growth).
If the inhibitors are homogeneously distributed through the matrix, the grain structure becomes slightly sensible to the thermal treatment, up to a temperature at which the specific inhibitors, with reference to their own thermodynamic stability into the alloy and to the metal matrix chemical composition, start modifying their dimensions through a process of dissolution or dissolution and growth, in any case with the net result of a progressive reduction of the number of precipitates (the grain growth physical phenomenon is controlled by the surface amount of second phases interfacing the metallic matrix).
At the same time of this process the grains boundaries can start to significantly move letting to grow those grains which can do it earlier and faster. If there was an appropriate process control during the whole cycle and during the final annealing, only few grains will selectively grow, for reasons well known to the experts, with the desired orientation, with an axis  less than 100 greater than  parallel to the rolling direction, according to the Miller indexes. The higher the temperature at which this process happens, the better is the orientation of the grown grains and the better are the final magnetic characteristics of the product.
Each kind of inhibitor has it own solubilization temperature, rising from the sulphides and selenides to nitrides. Due to the slow heating of the coils in the final box annealing, the real solubilization temperature of the inhibitors essentially corresponds to the thermodynamic one, and hence the secondary recrystallization temperature is fundamentally linked to the inhibitor type utilised and to the alloy composition.
Therefore, the possibility to enhance the magnetic characteristics of the final product is roughly limited essentially by the dissolution temperature of the chosen inhibitor.
It is useful, at this point, to remind how the inhibitors useful for the grain growth control are formed.
During the relatively slow solidification processes of the liquid steel during the casting thereof and the subsequent cooling, the elementary components of the inhibitors, which unhomogeneously concentrate in some zones of the matrix due to the segregation enhanced by the slowness of such processes, can easily aggregate in unevenly distributed coarse particles, useless for an effective inhibition of the grains boundaries movement, and hence for the growth thereof, up to the desired temperature.
Since the transformation process of silicon steel down to a strip comprises a number of high temperature treatments, obviously in each one of said treatments an uncontrolled grain growth could start, with a consequent, probably high, loss of quality. This is the reason why the processes commonly utilised for the production of electrical steel strips comprise a high temperature treatment of the continuously cast body (usually a slab), to dissolve the coarsely precipitated inhibitors, to be later reprecipitated in a more fine and uniformly distributed form.
After this treatment, all the other high temperature treatments must be carefully controlled to avoid or limit the variations in the dimensional distribution of the second phases particles; such a control is obviously very delicate and difficult. Answering to the above problems it was proposed, for instance in U.S. Pat. No. 4,225,366 and EP 0 339 474, to radically modify this procedure, maintaining practically unmodified the coarse precipitates obtained during the steel solidification, performing all the subsequent treatments at temperature lesser than the usual ones, and forming the inhibitors useful for the grain growth inhibition only in the last steps of the process, through introduction of nitrogen into the strip, thus forming nitrides.
This technology which, at least as per its basic aspects, was proposed in 1966 (Japan Patent application, priority number 41-26533), still has some inconveniences at the industrial level, among which the fact that, due to lack of inhibitors, all the thermal treatments, even at relatively low temperatures, must be carefully controlled to avoid an undesired grain growth, and that the distribution of inhibitors, useful for the control of grain growth and of oriented secondary recrystallization, is obtained during the slow heating to the annealing temperature during the final box annealing, either through nitrogen permeation directly in this phase, and subsequent diffusion and precipitation as nitrides throughout the thickness of the strip, or through a continuous nitriding (before the box annealing) which, however, is necessarily limited at not so high temperatures thus producing, at the strip surface, the precipitation of low-stability nitrides, substantially with silicon which, being abundantly present in the metal matrix, will bond the nitrogen near the strip surface, blocking its further diffusion. Such silicon based nitrides are useless for the desired grain growth inhibition and, only during the subsequent slow heating in the box annealing, will decompose thus releasing nitrogen which can now diffuse into the strip and form the desired stable aluminium-based nitrides (Takahashi, Harase: Materials Science Forum, 1966, Vol. 204xe2x80x94204, pages 143-154; EP 0 494 730 A2, page 5, lines 3-44).
This Applicant, aware of the difficulties proper of the known processes for the production of oriented grain electrical steel strips, did develop an original and highly innovative technology, according to which it is useful to permit in the continuously cast steel, after the high temperature annealing of the cast body, or after the hot rolling, the formation of a limited quantity of useful inhibitor precipitates, to attenuate the criticality of the treatment temperatures, and, more specifically, to utilize during the continuous nitriding sufficiently high temperatures to consent the penetration of nitrogen throughout the strip thickness and, at the same time, to directly form aluminium-based nitrides, having a morphology useful to control the grain growth inhibition.
The above technology is described in the PCT Applications PCT/EP97/04005, PCT/EP97/04007, PCT/EP97/04080 and PCT/EP97/04089. Tough the above described new technologies represent important steps in the production of electrical steel strips, either of the xe2x80x9cconventional oriented grainxe2x80x9d type (with magnetic permeability up to about 1890 mT) or of the xe2x80x9csuper-orientedxe2x80x9d type (with magnetic permeability higher than 1900 mT), there are still many important points requiring extensive studies and adequate solutions.
Among such points there is the static box annealing which, as previously described, is still considered essential for the obtainment of the desired magnetic properties and world-wide utilised by the electrical steel producers, though presenting important problems of productivity, costs and process control.
An object of the present invention is to obviate to the described inconveniences, proposing a process in which the secondary recrystallization, up to now obtained exclusively in the box annealing furnaces, is realised, or at least significantly started, in a quick continuous treatment following the primary recrystallization and the nitriding with direct formation of aluminium-based nitrides, thus making it possible to have a more adequate process control during the oriented secondary recrystallization phase, and permitting to chose the recrystallization starting temperature, thus facilitating and rendering less critic the box annealing furnaces management.
According to present invention, a process for the production of grain oriented electrical steel strip comprising the steps of (i) preparing a silicon steel liquid bath of desired composition, (ii) continuously casting said steel, (iii) treating the continuously cast body at a temperature of between 1100 and 1300xc2x0 C., to correct the heterogeneous distribution of inhibitors in the cast body through their non complete solubilization and subsequently hot rolling to reprecipitate in a fine and uniformly distributed form the inhibitors previously dissolved, to obtain a given level of homogeneous inhibition, (iv) cold rolling the steel, is characterised by the combination in co-operation relationship of the following steps:
a) cold rolling with a reduction rate of at least 70%,
b) continuous annealing for primary recrystallization at a temperature comprised between 700 and 1000xc2x0 C., preferably between 800 and 900xc2x0 C., also comprising possible decarburization and controlled superficial oxidation phases;
c) subsequent continuous treatment at a temperature comprised between 800 and 1100xc2x0 C., preferably between 900 and 1000xc2x0 C., in a nitriding atmosphere apt to directly obtain nitrides useful for the grain growth inhibition up to a high temperature, evenly distributed throughout the strip thickness;
d) further continuous treatment at a temperature comprised between 1000 and 1200xc2x0 C., preferably between 1050 and 1150xc2x0 C., in a nitrogen-hydrogen containing atmosphere to carry out, or at least start, the secondary recrystallization process;
e) possible further continuous thermal treatment at high temperature.
This last high temperature treatment can be carried out in a nitriding atmosphere. The steel to be used according to present invention comprises, in weight percent, the following elements: Si 2.0-5.5; C 0.003-0.08; Als 0.010-0.040; N 0.003-0.010; Cu 0-0.40; Mn 0.03-0.30; S 0.004-0.030; Snxe2x89xa60.20; also other elements can be present such as Cr, Mo, Ni, in a total amount lesser than 0.35% b/w. Moreover, also other useful nitride-forming elements can be present, such as Ti, V, Zr, Nb. The remaining of steel is essentially iron and unavoidable impurities.
Preferably, some elements must be present in the following amounts, in weight percent: C 0.03-0.06; Als 0.025-0.035; N 0.006-0.009; Mn 0.05-0.15; S 0.006-0.025. Copper can also be present in amounts comprised between 0.1 and 0.2% b/w.
The liquid steel can be continuously cast in any known method, also utilising thin slab or strip continuous casting.
During the cooling after the high temperature heating of the continuous cast body, and during the hot rolling, working conditions are utilised, known to the experts, such to obtain a level of useful inhibition comprised between 300 and 1400 cmxe2x88x921, expressed by the formula:
lz=1,9 fv/r
in which lz is the inhibition level, fv is the volumetric fraction of useful precipitates and r is the mean dimension of same precipitates.
The grain dimensions produced during the primary recrystallization and the subsequent controlled growth are adjusted through decarburization temperature and duration; the relationship between those two treatment parameters and the obtained grain dimensions depends on the utilised chemical composition, on the cast body heat cycle and on the strip thickness.
The grain dimensions obtained before the nitriding treatment depend also on the time the strip takes to reach the treatment temperature during the continuous treatment.
For example, following table 1 shows the correlation between grain dimensions and treatment temperature, for a steel strip 0.30 mm thick, containing Al 290 ppm, N 80 ppm, Mn 1400 ppm, Cu 1000 ppm, S 70 ppm, hot rolled with a slab heating temperature of 1300xc2x0 C.; the grain dimensions were obtained analysing rolled specimens processed at different temperatures in the first part of the continuous thermal treatment, and stopping the treatment before the high temperature nitriding step.
If steel compositions are utilised having very low carbon content, it can be not necessary to control the decarburization, usually associated to the primary recrystallization.
The nitrogen which deeply penetrates into the steel strip during the high temperature nitriding, preferably forms aluminium-based nitrides. However, in the present invention, it is also possible to utilize other useful nitride forming elements, such as, for instance, Ti, V, Zr, Nb.
The high temperature treatment following the nitriding step is meant to start, and possibly to complete, the oriented secondary recrystallization. Indeed, it is possible to complete the nitriding step in a time lesser than the one of strip transit in the nitriding furnace. This can advantageously utilised to at least start the secondary recrystallization within the nitriding furnace. However, the continuous treatment tending to at least start the secondary recrystallization could also be carried out in another furnace, even after the strip cooling.
By the expression xe2x80x9cstarting of the oriented secondary recrystallizationxe2x80x9d the process is meant according to which a small fraction of the grains, present in the matrix and having the orientation desired for the final product, start to quickly and significantly grow, reaching a dimension strikingly different (greater) than the one of the remaining grains (mean dimension). In the present invention, the selective growth of said fraction of grains is such that the interested grains can be seen with the naked eye (their major dimension being evaluated at around 0.3 mm) at the end of the continuous annealing treatment, after an appropriate sample preparation.
At least some of the various heating steps of the process above described, can be carried out at high speed, of about 400-800xc2x0 C./s; in such a way the time can be raised during which the strip can be maintained at the treating temperature, the plant length being equal, thus rising the process productivity.
Moreover, as it is known, a quick heating at high temperature for the primary recrystallization results in a larger number of crystalline nuclei being involved in the process as well as of the crystals that subsequently can grow. Consequently, to the secondary recrystallization will correspondingly participate a larger number of grains, speeding up the secondary recrystallization process, which starts and ends earlier.
Obtaining the treating temperature at such a high speed, and however at the typical speed of the continuous annealing treatments, during the third phase of the cycle according to present invention (immediately after the nitriding step) allows to a priori define the temperature at which the secondary recrystallization will start, contrary to the process in the box annealing furnaces in which, due to the inevitably low heating speed, the secondary recrystallization starting temperature is linked in a complex and not controllable way to the kind of inhibitor utilised and to the ensemble of conditions and micro-environments which are established on the strip surface during the long treatment cycle.
According to present invention, the secondary recrystallization starting temperature as well as the temperature at which the same recrystallization develops and ends, are largely independent from thermodynamic and phisico-chemical limits such as the solubility of inhibitors components, diffusion coefficients, grain boundary mobility, and so on.
The realisation, or at least the starting, of the secondary recrystallization process during a continuous treatment subsequent to the primary recrystallization and to the formation of the desired inhibition within the strip metal matrix, allows also a very precise control, at the industrial scale production cycles, of the annealing conditions (e.g. temperature and composition of the annealing atmospheres). Such conditions can be ensured as constant on the whole length and width of the strip, and can be adjusted, according to the necessity, for each coil.
A further important characteristic of the present invention is the possibility to have a control of the final annealing process conditions, directly measuring at the exit of the continuous treatment line the magnetic characteristics resulting from the development of the secondary oriented recrystallization.
The use of continuous measures of magnetic characteristics at the end of a dynamic annealing treatment is a known technique, in some cases well established, to indirectly evaluate other metallurgical characteristics of the steel strip, such as the grain dimensions.
In this case, a direct measurement of the functional characteristics of the product can be performed, with obvious advantages on the process control practice. As far as the above is concerned, it is important to remind that in all the present production cycles of grain oriented electrical steel strip, practically utilised and also just described in the literature, the oriented secondary recrystallization is started and completed in a static annealing, and thus once started the annealing, involving usually a number of coils at the same time, it is impossible to change the treatment conditions in order to influence the results thereof. The final magnetic characteristics can, in fact, be evaluated only at the end of the subsequent treatment of thermal flattening and coating.
In the industrial practice, this is a dangerous limit which the producers were forced to accept up to now; should, however, some troubles creep in the process control during the production cycle, this could mean production of large quantities of product with low or even unacceptable quality, well before the recognition that some trouble occurred.
According to the present invention, after the secondary recrystallization in a continuous cycle, the strip can also be continuously treated to eliminate the nitrogen, now no more useful, as well as other elements detrimental for the steel final quality, and to undergo a final treatment to form protective and insulating coatings. With respect to this last treatment, it is also possible to carry out a bright annealing treatment, or the like, avoiding the formation of the glass film, in the case other type of coating are to be utilised, for instance thinner ones, to improve the space factor in the production of the final goods, for instance transformer cores.
The steel which underwent the secondary recrystallization annealing can also be further treated in box furnaces, for instance in order to eliminate sulphur; this treatment, however, is no more rigidly limited by thermal gradients, heating velocity and the like, hence its duration is drastically reduced.
The strip produced by the continuous treatment line can directly represent the final product, not considering a further insulating coating treatment to be carried out in another line, but which can be carried out also a continuous sequence process on the same line in which the primary recrystallization, the grain growth and the secondary recrystallization are obtained.
The technical and qualitative aspects of the present invention will now be illustrated with the following Examples, to be considered exclusively explicatory and not limiting of the characteristics and scope of present invention.

Process for the production of grain oriented electrical steel strips