The present invention is a device for measuring the temperature of a molten metal. The device includes a thermocouple element, a housing consisting of a heat-resistant material and a retainer member for receiving the thermocouple element. The retainer member has an open end and a closed end. The thermocouple element has a hot junction located proximate the closed end of the retainer member. The retainer member is positioned within the housing and is smaller in size than the housing to define a cavity therebetween. The cavity is substantially filled by a protective material which includes a metal oxide component and an oxygen reducing component.

The temperature of molten metal processes may exceed 3000.degree. F. Thermocouple devices for monitoring the temperature of a molten metal must resist deterioration when subjected to high temperatures and a highly reactive molten metal environment while providing accurate temperature measurements for controlling the temperature of the melt.
Typically, a thermocouple consists of a positive element and a negative element joined at each of their respective ends such that a measurable electric current flows in a continuous circuit through the elements depending upon the temperatures of the two junctions at which the elements are joined.
The positive and negative elements may, for example, be formed from wires of different metals. The combination of a positive element of platinum/30% rhodium and a negative element of platinum/6% rhodium is useful for measuring temperatures ranging from about 1600.degree. to about 3100.degree. F. Another typical positive element/negative element thermocouple combination is platinum/13% rhodium and platinum, which is suitable for measuring temperatures ranging up to about 2700.degree. F.
The positive and negative elements are joined at a hot junction, which is subjected to the temperature of the molten metal. The positive and negative elements may be joined by any means that will ensure good electrical contact when in use. Typically, the positive and negative wires are twisted together and welded to form the hot junction.
The metal components of the thermocouple, particularly platinum, are expensive. Therefore, it is desirable to shield the elements from the harsh environment of the molten metal to prolong the useful life of the thermocouple and lessen the frequency at which the thermocouple must be replaced, as well as to ensure the accuracy of temperature measurements. Consequently, in industrial applications, the thermocouple is usually placed within a protective tube.
In the prior art, there is disclosed a closed-end protective tube which encloses a thermocouple element. The thermocouple element may be formed from platinum. The protective tube is disposed in a protective outer sheath consisting generally of a heat-resistant metal oxide and graphite. An annulus or cavity is generally formed between the exterior of the closed-end protective tube and the interior of the protective outer sheath. Unfortunately, silicon monoxide and carbon monoxide may be formed in the cavity of such a device when the device is subjected to the high temperatures of the metal melt. These highly corrosive and reactive gases may penetrate the material of the closed-end protective tube. Carbon monoxide may increase the porosity and damage or destroy the protective tube. A damaged tube permits silicon monoxide to react with and damage or destroy the thermocouple element. The temperature measurements derived from the damaged thermocouple element may be faulty or nonexistant.
Also disclosed in the prior art is a thermocouple element encased in a closed-end ceramic coated impermeable molybdenum tube. The tube is embedded in a protective sheath consisting of a plurality of ceramic layers, the concentration of molybdenum decreasing in each successive outer layer. The layers compensate for temperature gradients along the length of the molybdenum tube. The ceramic coated tube is embedded in a protective sheath by a ceramic mass. In addition to being extremely expensive and difficult to produce, this device is susceptible to mechanical damage during routine handling.
The present invention comprises a thermocouple device which provides protection against chemical attack by the harsh molten metal environment. The device also prevents formation of reactive gases, such as silicon monoxide or carbon monoxide within the device, which are capable of damaging or destroying the thermocouple element. By increasing the life expectancy of the thermocouple element, the present temperature sensing device provides more accurate temperature measurements which enable the melt to be more closely controlled. By increasing the lifetime of the thermocouple element, the device may be replaced less often and the associated costs of replacement, such as disassembling and reassembling process equipment, may be ameliorated.

Device for measuring the temperature of a molten metal


A punching apparatus used for high speed punching of holes in a workpiece, such as a ceramic green sheet, for use as a printed-circuit board. Upper and lower die blocks, stationary relative to each other, are provided, with punch pins fixed in two dimensions by multiple guides. A fluid passage is provided within the lower die block for providing gaseous lubrication and cleaning of the punch pin while in operation.

1. Field of the Invention
This invention relates to a punching apparatus for making or forming holes, and more particularly, to a punching apparatus for making holes in a workpiece or matter to be worked such as ceramic green sheet (referred to simply as "green sheet", hereinafter).
2. Background Art
It is generally known to use a multilayer printed-circuit board of ceramic as a substrate of a semiconductor integrated-circuit device, for example, used in a large-scale computer and the like. This kind of ceramic substrate or board is generally manufactured in such a manner that a basic substrate called green sheet, which is formed by a sheet-like sinter of alumina, is first formed therein with through holes by a punching apparatus and, then, a conductive paste of molybdenum (Mo) or tungsten (W) is printed on the surface of the substrate in the fixed pattern and, at the same time, filled in the inner walls of the through holes, and thereafter, a fixed number of these substrates are laminated and subjected to the sintering at a time.
By the way, the performance of the multilayer printed-circuit board or substrate depends on whether or not the through holes serving to electrically connect the printed circuit conductor layers of the multilayer printed-circuit ceramic substrate to each other are formed in correct positions with correct size and whether or not the through holes are formed without damaging the substrate around the through holes. For this reason, in case of manufacturing the multilayer printed-circuit ceramic substrate, it is an important manufacturing process that the through holes are formed in correct positions without damaging the substrate around the through holes.
Examples of the conventional punching apparatus for making through hole include the punching apparatus disclosed in Japanese Patent Unexamined Publication Nos. 1-171800 and 2-59299. This kind of punching apparatus comprises a lower die block having a flat upper surface on which a green sheet as a sheet-like matter to be worked is to be put and a plurality of first penetrating holes each extending from the upper surface perpendicularly thereto and located in a position where a hole is to be made in the matter to be worked, an upper die block having a lower surface arranged close to the upper surface of the lower die block so as to be opposed to the upper surface thereof and a plurality of second penetrating holes each extending from the lower surface perpendicularly thereto and located in a position opposite to an opening at the upper end of the first penetrating hole, and a plurality of punch pins each having a shaft portion and a cutting edge portion located at the lower end of the shaft portion and inserted in the second penetrating hole movably along the second penetrating hole so as to project the cutting edge portion out from the second penetrating hole of the upper die block, in which punching apparatus the upper die block has a bearing portion in the axial central part of each second penetrating hole for serving to support the shaft portion of the punch pin for free sliding movement along the second penetrating hole.
The present inventors use a punching apparatus having a working section of the construction shown in FIG. 10 in one of the inventors' companies, which apparatus was obtained by improving the punching apparatus disclosed in the above publications and, hence, is not known in public.
In the punching apparatus of FIG. 10, a green sheet 201 to be subjected to punching is put on a die base 202 of a lower die assembly 250 of the punching apparatus, and a die 203 is fixed in a hole 251 of the . die base 202.
An upper die body 260 of the punching apparatus comprises a base plate 204 as an upper plate, a punch pin support body 205 fixed to the underside of the base plate 204, and a stripper plate 206 as a lower plate fixed to the underside of the punch pin support body 205.
A sleeve 207 is inserted in a penetrating hole 261 of the punch pin support body 205, and a ball guide 208 is inserted in the sleeve 207.
In a penetrating hole 262 of the base plate 204, a lower spring shoe 209 is inserted so as to be brought into contact with the upper surface of the punch pin support body 205 and, further, a spring 210 is inserted so as to be brought into contact with the upper surface of the spring shoe 209.
Further, in the penetrating hole 262 of the base plate 204, an upper spring shoe 211 is inserted so as to be brought into contact with the spring 210. A pin holder 213 formed with a flange 212 serving to come in contact with the spring shoe 211 is inserted in the ball guide 208 so as to be movable in vertical directions A and B.
A pin sleeve 214 having a flange 214a is put on and inserted in the upper portion of the pin holder 213. A punch pin 215 having a cutting edge 216 formed at one end thereof and extending through the base plate 204, the punch pin support body 205 and the stripper plate 206 is inserted in the pin sleeve 214.
The pin sleeve 214 is fixed to the punch pin 215 by means of a screw 219 screwed to one end of the pin sleeve 214 with its one end 217 being in contact with a large diameter upper end 218 of the punch pin 215. Upward movement of the pin holder 213 in the direction A is limited by a stopper plate 220 fixed to the base plate 204.
A set bush 221 is disposed in and fixed to the pin holder 213 at a lower portion thereof for serving to set a horizontal position of a shaft portion 263 of the punch pin 215 adjacent to the cutting edge 216.
In a working section 200 of the above construction, as the green sheet 201 is put on the die base 202 in position, a driving means which is not shown drives the punch pin 215 to move downward in the axial direction B under the guidance of the ball guide 208, thereby making a through hole 222 in the green sheet 201.
The diameter of the through hole 222 to be formed in this way has been reduced with the increase in mounting density and degree of integration, and now, it is required to make a through hole of diameter less than 0.2 mm. Further, increase of the number of through holes 222 causes the diameter of the cutting edge 216 of the punch pin 215 to be reduced as well, and a clearance C between the cutting edge 216 of the punch pin 215 and the die 203 has been required to be about 0.01 to 0.03 mm, more preferably as small as 0.001 mm, on one side.
In addition, in order to improve the efficiency of the punching operation, it is also required to increase the number of punch pins 215 to be disposed in the punching apparatus. For this reason, the punch pin 215 to be built in the punching apparatus 200 is needed to become further thin, and now, the outside diameter of the shaft portion thereof has become about 0.3 to 1 mm.
However, the above punching apparatus 200 according to the proposed technique is constructed with the intention of positioning the punch pin 215 with high accuracy so that the positioning structure thereof is very complicated. In consequence, the number of component parts is increased, resulting in a problem that it is difficult to obtain a high positional accuracy of the punch pin 215 under the influence of not only the error in making the penetrating hole 261 in the punch pin support body 205 but also the error in finishing the parts to be disposed in the hole 261 including the sleeve 207, the ball guide 208 and the pin holder 213 as well as the cumulative error appearing when the parts are combined.
Further, since it is necessary to provide a structure for stopping the leakage of the lubricating oil from the ball guide 208, such as a groove 223, in the stripper plate 206, the set bush 221 of the punch pin 215 is disposed at a distance from the upper surface 224 of the die base 202 and the cutting edge 216 of the punch pin 215, resulting in a disadvantage that it is very difficult to obtain a high positional accuracy of the cutting edge 216 of the punch pin 215.
On the other hand, complication of the above structure and increase of the number of parts make it difficult to dispose a large number of punch pins 215 in the upper die block at high density.


A retractable barrier system for preventing unsupervised access to dangerous areas by children. The retractable barrier system includes an housing with an elongate perimeter wall, a bottom wall and a top wall which define an interior space; a barrier assembly positionable within the housing and extending through a slot of the housing; a biasing assembly for selectively retracting the barrier assembly into the housing; a receiving housing for selectively coupling to the barrier assembly; and an alarm assembly positioned within the receiving housing to provide an aural warning when the barrier assembly is disconnected from the receiving housing.

1. Field of the Invention
The present invention relates to child safety barriers and more particularly pertains to a new retractable barrier system for preventing unsupervised access to dangerous areas by children.
2. Description of the Prior Art
The use of child safety barriers is known in the prior art. More specifically, child safety barriers heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art includes U.S. Pat. No. 5,249,315; U.S. Pat. No. 5,102,103; U.S. Pat. No. 5,152,508; U.S. Pat. No. 4,005,397; U.S. Pat. No. 5,771,505; and U.S. Pat. No. Des. 388,867.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new retractable barrier system. The inventive device includes an housing with an elongate perimeter wall, a bottom wall and a top wall which define an interior space; a barrier assembly positionable within the housing and extending through a slot of the housing; a biasing assembly for selectively retracting the barrier assembly into said housing; a receiving housing for selectively coupling to the barrier assembly; and an alarm assembly positioned within the receiving housing to provide an aural warning when the barrier assembly is disconnected from the receiving housing; or tampered with while connected to the receiving housing.
In these respects, the retractable barrier system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of preventing unsupervised access to dangerous areas by children.
In view of the foregoing disadvantages inherent in the known types of child safety barriers now present in the prior art, the present invention provides a new retractable barrier system construction wherein the same can be utilized for preventing unsupervised access to dangerous areas by children.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new retractable barrier system apparatus and method which has many of the advantages of the child safety barriers mentioned heretofore and many novel features that result in a new retractable barrier system which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art child safety barriers, either alone or in any combination thereof.
To attain this, the present invention generally comprises an housing with an elongate perimeter wall, a bottom wall and a top wall which define an interior space; a barrier assembly positionable within the housing and extending through a slot of the housing; a biasing assembly for selectively retracting the barrier assembly into said housing; a receiving housing for selectively coupling to the barrier assembly; and an alarm assembly positioned within the receiving housing to provide an aural warning when the barrier assembly is disconnected from the receiving housing; or tampered with while connected to the receiving housing.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new retractable barrier system apparatus and method which has many of the advantages of the child safety barriers mentioned heretofore and many novel features that result in a new retractable barrier system which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art child safety barriers, either alone or in any combination thereof.
It is another object of the present invention to provide a new retractable barrier system which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new retractable barrier system which is of a durable and reliable construction.
An even further object of the present invention is to provide a new retractable barrier system which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such retractable barrier system economically available to the buying public.
Still yet another object of the present invention is to provide a new retractable barrier system which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new retractable barrier system for preventing unsupervised access to dangerous areas by children.
Yet another object of the present invention is to provide a new retractable barrier system which includes an housing with an elongate perimeter wall, a bottom wall and a top wall which define an interior space; a barrier assembly positionable within the housing and extending through a slot of the housing; a biasing assembly for selectively retracting the barrier assembly into said housing; a receiving housing for selectively coupling to the barrier assembly; and an alarm assembly positioned within the receiving housing to provide an aural warning when the barrier assembly is disconnected from the receiving housing; or tampered with while still connected to the receiving housing.
Still yet another object of the present invention is to provide a new retractable barrier system that is positionable in front of or over bathtubs to prevent scalding or drowning.


A computer-readable recording medium having stored therein a program for causing a computer to execute a digital signature process, wherein the digital signature process includes distributing packets to machines based on session durations according to a communication of the packets in a given duration, and performing verification tests based on the packets distributed to the machines by each of the machines.

After operation for applying a patch to a server, updating firmware, changing the server from a physical server to a virtual server, or the like, a test is performed to verify whether the server operates as before the operation. The above-described test is called a verification test. It may take long to rigorously perform the verification test. Thus, there is a demand for a technique for performing the verification test in a short period of time.
According to the technique for performing the verification test, a control unit stores data (that is, capture data), which is obtained by adding a time stamp to reception data based on a real time clock, in a storage unit in a chronological order. A start time of a system time may be set to any time. When the start time is set, the system time is regularly updated based on a real time clock. When there is an instruction of simulation transmission, the data with the time stamp corresponding to the system time is sequentially transmitted to a low rank system. When a new start time is set in a direction where the system time is set forward, untransmitted data with the time stamp of a time that is older than the new start time is extracted and is then high-speed transmitted at short telegram message intervals. Due to this, retransmission is performed at substantially the same timing as actual transmission intervals, and a reproduction test of failure occurrence is performed. Further, as for part that is not typically reproduced conscientiously, the high-speed transmission is performed at the short telegram message intervals to effectively perform simulation.
If the transmission interval of the data is shorter than the actual transmission interval, the load of the system that performs the verification test increases. The part in which the transmission interval may be shortened is limited.
Japanese Laid-open Patent Publication No. 2010-81194

Computer-readable recording medium, information processing method, and information processing apparatus


A method of encoding a video data including a plurality of pictures includes storing data of at least one picture in the video data that is already encoded, and referring to the stored data and using intra-prediction to encode blocks in a current picture.

1. Field
Embodiments of the present invention relate to video data processing and, more specifically, to a method and an apparatus for encoding and decoding video data.
2. Description of the Related Art
H.264/MPEG-4 Advanced Video Coding (AVC), which is one of compression standards of video data, adopts various technologies for increasing compression efficiency, such as multiple reference motion compensation, loop filtering, variable block size motion compensation, entropy coding, such as CABAC, etc.
According to the H.264 standard draft, one picture is divided into macroblocks to encode video data. Then each of the macroblocks is encoded in all encoding modes available in inter-prediction and intra-prediction, one encoding mode is selected according to a bit rate required for encoding the macroblocks, a distortion degree between original macroblocks and decoded macroblocks is determined, and then the macroblocks are encoded.
Intra-prediction refers to a technology that, rather than refer to a reference picture to encode blocks of a current picture, calculates a prediction value for the current picture to be encoded by using pixel values that are spatially adjacent the current picture to be encoded, and then encodes a difference between the prediction value and an actual pixel value. Here, the intra-prediction mode is largely divided into a 4×4 intra-prediction mode (for luminance components), an 8×8 intra-prediction mode (for a high profile), a 16×16 intra-prediction mode, and an intra-prediction mode for chrominance components.

Method and apparatus for encoding and decoding image


A system, apparatus, and method for detecting the presence and amount of liquid and/or solid excrement in diapers or other undergarments, using a miniature ultra-low power near-field electromagnetic probe, applicable circuitry, and additional sensor types, that is hand-held or attached to the outside of said garments

In all human cultures where infants, babies, and toddlers wear clothing, the issue of determining when underclothing such as diapers need to be changed represents a continuous nuisance, medical risk, expense, and waste of time. A similar issue exists for infirm adults, especially those who cannot communicate.
Often, babies are aroused from sleep unnecessarily to check a diaper, causing harm to them and disruption to caregivers. During automotive travel, it may be necessary to pull over and stop the vehicle in what may be unsafe or inclement conditions, just to determine whether a diaper needs to be changed. If a diaper is checked too late, the consequences could be painful and dangerous chafing and/or infiltration to other clothing and surrounding objects. The diaper wetness monitoring task is magnified when there are multiple babies or infirm patients.
Many sensing methods that automatically provide an alarm when a diaper has become wet have been advanced during the past twenty years or so. All of them require special diaper construction and/or devices that mount inside the diaper or other undergarment and make physical contact with excrement. Moreover, they are sensitive only to liquid waste.
In contrast, the methods described in the instant disclosure are sensitive to liquid and solid waste. They require no special clothing construction and employ only miniature electronic devices that are either hand held or attached to the outside of a diaper or other undergarment. The single device can be used repeatedly for a period of years with no maintenance, and it could include communication with the caregiver via wireless means. Moreover, the device itself and method of attachment to clothing are intrinsically safe for infants and babies.

Contactless magnetic probe sensing and impedance imaging of liquid and solid excrement in diapers and other underclothing


This invention relates to a method of evaluating monomers having an effect on copolymer characteristics and a system using the same, and particularly to a novel method of evaluating the magnitude of the effect of monomers on copolymer characteristics, which cannot be evaluated using existing methods. The method of evaluating monomers having an effect on copolymer characteristics and the system using the same are innovative because the extent of changes in copolymer characteristics can be predicted at the monomer level by quantitatively evaluating the effect of the monomers on the copolymer characteristics, taking into consideration the kind or linkage type of monomers.

A copolymer is a material synthesized by linking one or more monomers through a variety of polymerization processes, and is widely utilized in material development and other fields because the properties or characteristics thereof may be controlled at various levels so as to be suitable for respective end uses. One of the factors that greatly affect the characteristics of the synthesized copolymer is the monomers that constitute the copolymer, and the copolymer characteristics vary significantly depending on the number, kind or linkage type of monomers, which are the basic repeating unit of the copolymer. Such changes in copolymer characteristics are determined by the complicated and subtle actions of numerous monomers for the copolymer, but methods of clearly evaluating the effects of monomers on the copolymer characteristics have not yet been devised. Meanwhile, a conventional experimental method (e.g. Gel Permeation Chromatography) is able to measure the properties of a copolymer, such as the molecular weight and viscosity of a copolymer, but is unable to evaluate the effect of the monomers constituting the copolymer on the copolymer characteristics. Therefore, in order to maximize the performance of a copolymer by improving copolymer characteristics and also to design and synthesize copolymers that exhibit new characteristics, there is a need to develop a novel method that is capable of evaluating the effect of monomers on a copolymer.

Method for evaluating monomers having effect on copolymer characteristics, and system using same


A transceiver comprising a transmitter and a receiver is a component of a user terminal. A transmitter-check signal is transmitted from the transceiver to a remote node. Errors in the transmitter-check signal are measured at the remote node. Transmitter-correction information based on the errors is determined within the remote node and sent back to the user terminal. The user terminal utilizes the transmitter-correction information to set a correction module in the terminal to counteract the errors within the transmitter.

Direct conversion receivers (a.k.a. homodyne or zero-IF receivers) and heterodyne receivers (a.k.a. low-IF receivers) are commonly used today to receive quadrature modulated signals sent over a communications network. The types of networks that use such receivers include satellite communication networks, wireless cellular networks, local access networks (LANs), wide access networks (WANs), as well as other types of communication networks. FIG. 1 is a simplified overview of a satellite communications network 100. The satellite communications network of FIG. 1 is an example, but it will be understood by those skilled in the art that the following discussion applies equally to other types of communication networks.
A gateway terminal (commonly referred to simply as a "gateway") 102 sends and receives signals to a satellite 104 through a satellite antenna 106. Signals transmitted from the gateway 102 to the satellite 104 are commonly referred to as forward uplink signals 108. Signals that are received by the gateway 102 from the satellite 104 are commonly referred to as return downlink signals 110.
The satellite 104 receives the forward uplink signals 108 sent from the gateway 102 and retransmits them to one or more user terminals 112 within the satellite communications network 100. Signals transmitted from the satellite to a user terminal 112 are commonly referred to as forward downlink signals 118. Signals received by the satellite from the user terminal 112 are commonly referred to as return uplink signals 120. Two user terminals 112 are shown. However, a typical satellite communications network 100 comprises many such user terminals. The user terminals 112 may be either fixed in their location or mobile terminals. Each user terminal 112 may have an antenna 122 and may comprise multiple elements including, for example, an outdoor unit (not shown), an indoor unit (not shown), and a link (not shown) there between.
In some cases, the gateway 102 communicates over a "backhaul" 116 with a terrestrial communications network 114, such as the Internet to allow the satellite 104 to connect a user terminal 112 to the terrestrial communications network 114.
FIG. 2 is a schematic of a portion of a direct conversion receiver, such as might be found in a user terminal 112 shown in FIG. 1. (As noted, a user terminal 112 can alternatively have a heterodyne receiver.) A composite quadrature receive signal 202 is applied to the data input of both an I-mixer 204 and a Q-mixer 206. A receiver local oscillator (LO) 208 is coupled to a phase splitter 210 that has an I-output that is at a reference phase (commonly referred to as 0 degrees) and a Q-output at the same frequency, but shifted 90 degrees with respect to the I-output. The I-output is coupled to the LO input of the I-mixer 204. The Q-output is coupled to the LO input of the Q-mixer 206. The outputs 212, 214 of the mixers 204, 206 are then digitized in analog-to-digital converters (ADC) 216, 218.
One problem that occurs with direct conversion receivers and to a certain extent with heterodyne receivers is that there can be an imbalance between the in-phase leg and the quadrature leg of either the transmitter from which the quadrature modulated signal is sent or the receiver that receives the signal. For example, imbalances in the amplitude or the phase of the in-phase signal 212 output by the I-mixer and quadrature signal 214 output by the Q-mixer can make it difficult to discriminate between symbols. That is, symbols are distinguished from one another based on the relative amplitude of the in-phase component 212 and the quadrature component 214 of the received signal 202. Therefore, differences in the gain and phase of the LOs or the path through the ADCs 216, 218 can lead to errors in identifying the symbol represented by the combination of in-phase and quadrature components of the received signal. Additionally, differences in the mixers 204, 206 and inaccuracy of the 90 degree phase splitter 210 can all result in an I/Q imbalance error. In addition, due to several causes that are well known in the art, it is possible for the output of the mixers 204, 206 to have a direct current (DC) offset. Such a DC offset can cause, among other problems, the ADCs 216, 218 to saturate prematurely.

Method and system in which a remote module assists in counteracting I/Q imbalance and/or DC offset errors


Methods of starting a wind turbine from a standstill substantially until generator connection, the wind turbine having a rotor with one or more blades, a pitch system for rotating the blades along their longitudinal axes and a generator operationally connected with the rotor. In standstill, the blades are substantially in a feathered position and the generator is not generating electrical power. The methods may comprise measuring the wind speed representative for the wind turbine and measuring the rotor speed of the wind turbine, and when the rotor speed is not equal to zero, determining the tip speed ratio for the wind turbine, and determining the pitch angle of the blades as a function of the tip speed ratio to optimize the torque produced by the blades of the wind turbine rotor.

Modern wind turbines are commonly used to supply electricity into the electrical grid. Wind turbines of this kind generally comprise a rotor with a rotor hub and a plurality of blades. The rotor is set into rotation under the influence of the wind on the blades. The rotation of the rotor shaft either directly drives the generator rotor ("directly driven") or through the use of a gearbox.
A variable speed wind turbine may typically be controlled by varying the generator torque and the pitch angle of the blades. As a result, aerodynamic torque, rotor speed and electrical power will vary.
A common prior art control strategy of a variable speed wind turbine is described with reference to FIG. 1. In FIG. 1, the operation of a typical variable speed wind turbine is illustrated in terms of the pitch angle (β), the electrical power generated (P), the generator torque (M) and the rotational velocity of the rotor (ω), as a function of the wind speed.
In a first operational range, from the cut-in wind speed to a first wind speed (e.g. approximately 5 or 6 m/s), the rotor may be controlled to rotate at a substantially constant speed that is just high enough to be able to accurately control it. The cut-in wind speed may be e.g. approximately 3 m/s.
In a second operational range, from the first wind speed (e.g. approximately 5 or 6 m/s) to a second wind speed (e.g. approximately 8.5 m/s), the objective is generally to maximize power output while maintaining the pitch angle of the blades constant so as to capture maximum energy. In order to achieve this objective, the generator torque and rotor speed may be varied so as keep the tip speed ratio λ (tangential velocity of the tip of the rotor blades divided by the prevailing wind speed) constant so as to maximize the power coefficient Cp.
In order to maximize power output and keep Cp constant at its maximum value, the rotor torque may be set in accordance with the following equation:T=k·ω2, whereink is a constant, and ω is the rotational speed of the generator. In a direct drive wind turbine, the generator speed substantially equals the rotor speed. In a wind turbine comprising a gearbox, normally, a substantially constant ratio exists between the rotor speed and the generator speed.
In a third operational range, which starts at reaching nominal rotor rotational speed and extends until reaching nominal power, the rotor speed is kept constant, and the generator torque is varied to such effect. In terms of wind speeds, this third operational range extends substantially from the second wind speed to the nominal wind speed e.g. from approximately 8.5 m/s to approximately 11 m/s.
In a fourth operational range, which may extend from the nominal wind speed to the cut-out wind speed (for example from approximately 11 m/s to 25 m/s), the blades may be rotated ("pitched") to maintain the aerodynamic torque delivered by the rotor substantially constant. In practice, the pitch is actuated such as to maintain the rotor speed substantially constant. At the cut-out wind speed, the wind turbine's operation is interrupted.
In the first, second and third operational ranges, i.e. at wind speeds below the nominal wind speed (the sub-nominal zone of operation), the blades are normally kept in a constant pitch position, namely the "below rated pitch position". Said default pitch position may generally be close to a 0° pitch angle. The exact pitch angle in "below rated" conditions however depends on the complete design of the wind turbine.
The before described operation may be translated into a so-called power curve, such as the one shown in FIG. 1. Such a power curve may reflect the optimum operation of the wind turbine under steady-state conditions. However, in non-steady state (transient) conditions, the operation may not necessarily be optimum.
As further background, basic aerodynamic behaviour of (the blades of) a wind turbine is explained with reference to FIGS. 2a-2e.
In FIG. 2a, a profile of a wind turbine blade is depicted in operation. The forces generated by the aerodynamic profile are determined by the wind that the profile "experiences", the effective wind speed Ve. The effective wind speed is composed of the axial free stream wind speed Va and the tangential speed of the profile Vt. The tangential speed of the profile Vt is determined by the instantaneous rotor speed ω and the distance to the centre of rotation of the profile, the local radius r, i.e. Vt=ω·r.
The axial free stream wind speed Va is directly dependent on the wind speed Vw, and on the speed of the wind downstream from the rotor Vdown, that is Va=½(Vw+Vdown). The axial free stream wind speed may e.g. be equal to approximately two thirds of the wind speed Vw.
The resultant wind flow, or effective wind speed Ve, generates lift L and drag D on the blade. A blade may theoretically be divided in an infinite number of blade sections, each blade section having its own local radius and its own local aerodynamic profile. For any given rotor speed, the tangential speed of each blade section will depend on its distance to the rotational axis of the hub (herein referred to as local radius).
The lift generated by a blade (section) depends on the effective wind speed Ve, and on the angle of attack of the blade (section) a, in accordance with the following formula:
      L    =                  1        2                          ρ        ·                  C          L                                            V          e          2                ·        S              ,whereinρ is the air density, Ve is the effective wind speed, CL is the lift coefficient (dependent on the angle of attack α) and S is the surface of the blade section.
Similarly, the drag D generated by a blade section can be determined in accordance with the following equation:
      D    =                  1        2                          ρ        ·                  C          D                                            V          e          2                ·        S              ,wherein CD is the drag coefficient, dependent on the angle of attack α.
For an entire wind turbine blade, the contribution to lift and drag of each blade section may be summed to arrive at the total drag and lift generated by the blade.
Both the drag coefficient CD and the lift coefficient CL depend on the profile or the blade section and vary as a function of the angle of attack of the blade section. The angle of attack α may be defined as the angle between the chord line of a profile (or blade section) and the vector of the effective wind flow.
FIG. 2b illustrates in a very general manner how the lift coefficient and drag coefficient may vary as a function of the angle of attack of a blade section. Generally, the lift coefficient (reference sign 21) increases to a certain maximum at a so-called critical angle of attack 23. This critical angle of attack is also sometimes referred to as stall angle. The drag coefficient (reference sign 22) may generally be quite low and starts increasing in an important manner close to the critical angle of attack 23. This rapid change in aerodynamic behaviour of a profile or blade section is linked generally to the phenomenon that the aerodynamic flow around the profile (or blade section) is not able to follow the aerodynamic contour and the flow separates from the profile. The separation causes a wake of turbulent flow, which reduces the lift of a profile and increases the drag significantly.
The exact curves of the lift coefficient and drag coefficient may vary significantly in accordance with the aerodynamic profile chosen. However, in general, regardless of the aerodynamic profile chosen, a trend to increasing lift up until a critical angle of attack and also a rapid increase in drag after a critical angle of attack can be found.
In accordance with FIG. 2a, the tangential force generated by a blade section is given by T=L·sin(α+ϑ)−D·cos(α+ϑ), wherein ϑ is the pitch angle and α is the angle of attack. The pitch angle may be defined as the angle between the rotor plane and the chord line of a profile. Integrating the tangential force distribution over the radius provides the driving torque.
In order to increase the torque generated by the rotor, the angle of attack of any blade section is preferably kept below the critical angle of attack such that lift may be higher and drag may be lower.
It should be borne in mind that the angle of attack of each blade section depends on the tangential speed of the specific rotor blade section, the wind speed, the pitch angle and the local twist angle of the blade section. The local twist angle of a blade section may generally be considered constant, unless some kind of deformable blade is used. The tangential speed of the rotor blade section depends on the rotor speed (angular velocity of the rotor which is obviously the same for the whole blade and thus for each blade section) and on the distance of the blade section to the rotational axis.
For a given pitch angle, it follows that the angle of attack is determined by the tip speed ratio:
  λ  =                    ω        ·        R                    V        w              .  From this, it follows that the torque generated by a rotor blade section may become a rather complicated function of the instantaneous tip speed ratio and the pitch angle of the blade.
This complicated relationship between the tip speed ratio, pitch angle, and performance (e.g. torque) of the rotor may be depicted in a three-dimensional figure, such as the one shown as FIG. 2c.
For every rotor blade section, the torque generated may be depicted by a line such as one of the lines shown in FIG. 2d of constant pitch angle or similar. (This FIG. 2d is from Erich Hau, "Wind Turbines, Fundamentals, Technologies, Application, Economics".)
These lines depict the torque coefficient (CQ), i.e, the ratio between the torque developed by the wind turbine rotor and the maximum theoretical torque. Such lines may be obtained by a cross-section of the plane of constant pitch angle with the plane depicted in FIG. 2c. For each pitch angle, there is a certain critical tip speed ratio for which maximum torque generation is achieved.
This may be illustrated in an alternative manner, such as shown in FIG. 2e. For a given tip speed ratio, e.g., λ1, there is a certain critical pitch angle ϑcrit. This critical pitch angle gives the before-mentioned critical angle of attack for the given tip speed ratio. Below the pitch angle, stall may occur. At the same time, at the critical pitch angle, the generated torque is maximum.
During start-up of a wind turbine from standstill to normal operation, the blades generally have to be rotated from a feather position towards an operational position. With reference to FIG. 3a, the blade may be rotated from a feathered position 32 towards an operational position 31, which in this case is shown to be an operation with zero degrees pitch, i.e. the chord line of the blade section lies in the plane of rotation.
However, the final operational position of the blade may depend upon the wind conditions at that specific moment. Start-up may be performed under conditions of generally low wind, e.g. because the wind turbine operation was interrupted because of relatively low wind speeds. Start-up may also be performed under conditions of relatively high wind speeds, e.g. because the wind turbine operation was interrupted at high wind speeds in order to avoid high loads on the wind turbine. Start-up may also be formed in any intermediate wind situation. This may be the case when wind turbine operation was interrupted for e.g. maintenance.
As the blade is rotated from a feathered position towards an operational position, the pitch angle will vary between approximately 90° (feather position) and the final pitch angle in operation, which could generally be in the range of e.g. 0°-30°. During start-up, the speed of rotation and thus the tangential velocity of a blade section may be relatively small as compared to normal operation. And as mentioned before, the wind speed could vary from very low to very high. The angle of attack of the blades may thus also vary widely.
During start-up, as the wind turbine rotor starts rotating and increases the rotor speed, and as the blade is pitched, the angle of attack of the blade undergoes a complicated transition. In this sense, the angle of attack of the blade may be defined as the angle of attack of a representative blade section. As explained before, each blade section may have its own angle of attack at any given moment. The representative blade section may be chosen at e.g. 25% of the blade length.
In a known method of starting-up a wind turbine, the blade is generally rotated at a given constant rate, regardless of the prevailing wind conditions, until the rotor starts rotating. This pitch rate is generally chosen to be relatively low, in order to avoid stall when the wind turbine is started up in conditions of relatively high wind speeds.
When the rotor starts rotating, the pitch rate is changed to a predetermined, higher second level, regardless of the prevailing wind conditions. This pitch rate is chosen to be higher so that the blades can speed up faster. If however, the pitch rate were chosen too high, under low wind speed conditions, stall could occur.
In the final phase of start-up, a look-up table of pitch angles vs. generator speed (or rotor speed) may be used until proper operation is started, i.e. until the generator is generating electrical power.
Using this method, start-up may take longer than needed, which means that less electrical power is generated.
In another method, disclosed in U.S. Pat. No. 4,160,170, both wind speed and rotor speed are taken into account during start-up. For different rotor speeds, blade pitch angles are established depending on the wind speed.
There still exists a need for a method of starting up a wind turbine which effectively reduces start-up time while simultaneously keeping blade loads etc. under control e.g. by avoiding stall of the wind turbine blade. This need is fulfilled in various examples of the present disclosure.


A self-propelled device movable inside a pipeline for the radiographic detection of flaws in its weld joints comprises a reversible drive motor and a normally deactivated radiation emitter. Logical circuitry aboard the device, including a two-stage memory, enables the selective energization of the drive motor and the activation of the radiation emitter during standstill in response to command pulses of different duration transmitted from an external radiation source through the pipeline wall and intercepted by one of two sensors.

Such self-propelled devices, also referred to as pipeline crawlers, are well known per se. They generally comprise reversible propulsion means energizable from without to advance or retract a mobile carrier inside a pipeline whose weld joints are to be tested by means of a normally deactivated radiation emitter aboard the carrier which is trainable upon these joints for panoramically illuminating same. Any flaw in the weld structure will show up on a radiation-sensitive strip surrounding the joint on the outer pipeline surface.
Earlier devices of this character utilized so-called umbilical cords connected outside the pipeline to a source of control signals. U.S. Pat. No. 4,006,359 describes a pipeline crawler responsive to commands transmitted through the pipeline in the form of pulses of radiant energy picked up by sensors aboard the device.

Apparatus for the control of self-propelled gamma-flaw detector

DSO "Montaji"--Kontrolno Zavarachno Upravlenie


Device for tightening a coiled covering wire of a composite piano string relative to the core wire thereof comprises a spring-loaded operating shaft axially movably encased within an elongated cylindrical main body, the shaft being provided with an outwardly exposable end portion adapted for detachable engagement with the top of a frame pin so that the composite piano string can be transferred to the shaft for twisting. Adjustment of the winding strength of the covering wire relative to the core wire is greatly simplified and stabilized.

The present invention relates to a covering wire tightening means or device for composite strings of pianos, and more particularly relates to a means advantageously used for eliminating slack winding of the covering wire on composite strings of pianos in order to improve tonal quality of tones to be generated.
As hereinafter described in more detail, a string for pianos is usually given in the form of a composite string particularly in the bass tone range. Such a composite string includes a core wire and a covering wire wound around the core wire.
It is known that a good tonal quality is obtained when the covering wire is relatively loosely wound around the core wire. However, gaps tend to be left between the wires by such a slack winding. Presence of such gaps generates unnecessary high frequency components when the string is hit by the hammer, thereby having ill influence on tonal quality of the tone to be generated. Therefore, a highly skilled technique is required in order to properly adjust the winding strength of the covering wire.
In order to eliminate such slack winding on a composite string, it is conventional practice to loosen the tuning pin for the ill wound composite string, disengage the composite string from the associated frame pin, twist by hand or suitable pincers the composite string in the winding direction of the covering wire, bring the fastened composite string back into engagement with the frame pin and stretch the composite string by adjusting the tuning pin.
However, strong resistance by the core wire against such twisting makes it quite difficult to successfully adjust the fastening strength of the covering wire in the above-described manner. Slight relaxation of the operator's hands during the adjustment allows easy restoration of the slack winding on the composite string. In addition, space limitation in the piano casing hinder free adjustment of the winding strength by operator's hands.

Covering wire tightening device composite strings of pianos


A surface treatment material for a metallic base of an artificial tooth is made of brazing filler metal which melts at a relatively lower temperature than melting points of components of the metallic base and which comprises fine powder of non-ferrous metal which boils at a brazing temperature and fine powder of non-ferrous metal which does not boil at the same temperature. By using the surface treatment material, a bonding strength between a facing portion of the metallic base and a formed material made of hard resin can be improved.

This application claims the priority of Japanese Patent Application No.5-62294(62294/1993) filed Mar. 23, 1993 and No. 5-245715(245715/1993) filed Sep. 30, 1993, which are incorporated herein by reference.
In a facing crown for an artificial front tooth, a tooth color hard resin is formed and bonded on a facing portion of a metal frame so as to get a natural appearance. But a bonding force between the hard resin and the metal frame is far from perfect. In order that the hard resin may be bonded firmly on the facing portion of the metal frame, a rugged outer surface is formed on the facing portion of the metal frame by use of retention beads, and then the rugged surface is plated with tin. By utilizing the retention beads, the surface area of the facing portion can be enlarged. And by tinning, the bonding strength of the formed material can be improved.
In spite of the combination of the retention beads and the tinning, however, the bonding strength between the hard resin and the facing portion of the metal frame is not sufficient. According to circumstances, there is a possibility that the formed material made of hard resin will peel off. In order to improve the strength of the bond between of the hard resin and the metal frame, a bonding strength accelerator such as a 4-methacryloxyethyl trimellitate anhydride will be applied before forming the hard resin on the facing portion of the metal frame. But in spite of using the bonding strength accelerator, the strength of bonding between the hard resin and the facing surface of the metal frame is not satisfactory.
This invention has been originated for overcoming the above difficulties. culties. A purpose of this invention is to provide a surface treatment material for a metallic base of an artificial tooth and a surface treatment process using such surface treatment material with high bonding strength between the facing portion of the metallic base and a hard resin formed on the metallic base.

Surface treatment material for a metallic base of an artificial tooth and a surface treatment process using the surface treatment material


A machine for transplanting potted seedlings grown in a series of pots linked together without separating them from one another includes a bottom plate having an upwardly curved leading end portion, and a slot formed in its trailing end portion. A soil opener is fitted in the slot and contains a vertically rotatable pot guide. A pair of soil drawing members are attached to the bottom plate behind the soil opener. A pair of side frames are erected on the bottom plate, and have inwardly directed portions converging toward the soil opener. A pair of pot guides are also provided on the bottom plate inwardly of the side frames.

1. Field of the Invention
This invention relates to a machine of the type placed on the ground which holds a series of pots linked together and each containing a seedling grown therein, and delivers the pots one after another from one end thereof for transplantation without separating the pots from one another, or from the seedlings.
2. Description of the Prior Art
A method which is widely used for transplanting seedlings employs square or hexagonal pots made of a thin material, such as paper. The pots are filled with soil, seeds are sown in the soil, seedlings are grown from the seeds under controlled sprinkling of water, and the potted seedlings are transplanted to a patch. There are two types of pots as classified by use for transplantation. A multiplicity of pots linked together for growing seedlings are separated into the individual pots prior to transplantation as disclosed in Japanese Patent Publication No. 25715/1963, or are supplied for transplantation in a chain without being separated from one another as disclosed in Japanese Patent Publication No. 30805/1980.
The decrease of manual labor has recently become essential in agriculture, too, as a result of the decrease in agricultural population, and the advance of ages of people engaging in agriculture. In this connection, the successive transplantation of seedlings by the latter type of pots has drawn attention, as it enables the fully automatic transplantation of seedlings by a machine.
There are known a number of transplanting machines. For example, Japanese Patent Publication No. 30805/1980 discloses a transplanting machine which includes two pairs of rotating members for holding two successive pots, respectively, which are linked together by a connecting material having a cut formed therein. The rotating members holding the preceding pot are rotated at a peripheral speed which is higher than that of the rotating members holding the following pot, whereby the connecting material is pulled and torn apart at its cut to enable the pots to be separated from each other for transplantation.
Japanese Patent Publication No. 61866/1988 discloses a transplating machine which includes a rotating disk having radially extending transplanting rods for holding a pot therebetween. When the disk is rotated to move the pot forward, a stop member is caused to act upon another, or the following pot linked to the preceding pot by a connecting material having a cut formed therein, whereby the connecting material is pulled and torn apart at its cut to enable the pots to be separated from each other for transplantation.
Japanese Patent Publication No. 28321/1979 discloses a series of pots linked together by a different connecting material having no such cut as described above. It is a decay-resistant string bonded to the centers of every two adjoining pots by a water-resistant paste, and having between every two adjoining pots a loose length which is equal to the distance between the seedlings to be transplanted. The string links the pots together in a multiplicity of rows, and every two adjoining rows of pots are bonded to each other by a water-soluble paste. The same publication also discloses a transplanting machine of the traction type which is movable on wheels contacting the ground for delivering the pots one after another from a platform, while allowing the string to be stretched between every two adjoining pots, and transplanting the potted seedlings successively without separating the pots from one another in the soil dug by a soil opener attached to the rear end of the platform.
The known machines, however, have drawbacks. The machine disclosed in Japanese Patent Publication No. 30805/1980 is adapted for handling relatively small pots and transplanting potted seedlings, such as of beets, at a spacing of 23 to 25 cm. The machine disclosed in Japanese Patent Publication No. 61866/1988 is adapted for handling relatively large pots and transplanting potted seedlings, such as of lettuce or cabbage, at a spacing of 30 to 45 cm. These machines are capable of transplanting potted seedlings at a spacing which is not smaller than, say, 10 cm, and are, therefore, incapable of transplanting potted seedlings of vegetables such as spinach and garland chrysanthemums, for which a transplanting spacing of 4 to 8 cm is usually appropriate. Moreover, a still smaller and simpler machine is desired for transplanting potted seedlings in a small area of land, as in a greenhouse.
The machine disclosed in Japanese Patent Publication No. 28321/1979 has a high platform level due to its wheels. Therefore, it is suitable for transplanting potted seedlings linked together by a loose and flexible material such as the string described above, but is not suitable for handling pots linked together by a material which forms an integral part of the pots, and is not loose or flexible, as disclosed in Japanese Patent Publication No. 30805/1980, since there is a limit to the angle at which the pots can properly be delivered from the platform to the ground. Any attempt to deliver the pots at a greater angle is very likely to cause the falling down of the pots or the breakage of the connecting material, and result in the interruption of any further delivery of the pots and thereby of transplantation work. The delivery of the pots within the limited angle is not always satisfactory, since it is likely that, as each pot is required to travel a longer distance from the high platform level to the ground, it may show a greater resistance to movement and thereby cause the connecting material to break.

Machine of the type placed on the ground for transplanting a series of potted seedlings


A fan system includes a rotor supported for rotation about a fan axis. The rotor has a central hub and a plurality of blades each extending outwardly from the hub to a tip. The rotor blades define a rotor plane perpendicular to the fan axis. A first acoustic resonator has an opening disposed on a first side of the rotor plane and a second acoustic resonator has an opening disposed on a second side of the rotor plane. The acoustic resonators are configured to provide a dipole resonator system operable to at least partially reduce a blade pass frequency tone in an upstream and a downstream direction simultaneously.

Axial turbomachinery noise is prevalent in many products ranging from large scale turbofan engines and compressor/turbine arrays to HVAC systems and computer cooling fans. Noise generated by turbomachinery has both broadband (due to the randomness of turbulent flow and its interaction with blade structures) and tonal components (due to periodic excitation of rotor blades and resonance sources). For subsonic axial fans, broadband noise results primarily from turbulent boundary layer scattering over a blade's trailing edge (TE), tip clearance noise and, potentially, from stall. Tonal noise results from rotor/stator interactions with time-invariant flow distortions and direct field interaction of rotor/stator blades. These tonal noise sources generally radiate axially for ducted fans as a dipole-like source. When spectrally dominant, blade tones are of primary concern in noise control applications due to their particular annoyance. Therefore, robust, cost-effective techniques for reducing their propagation are regularly sought.
Prior approaches used to reduce blade tone sound pressure levels (SPLs) have utilized both active and passive noise control methods. Passive blade alterations, such as rotor/stator spacing, leaning, sweeping or contouring, numbering, and irregular circumferential blade spacing, have been demonstrated effective for fan noise reduction. Also, absorbing liners or other duct cancellation techniques such as Herschel-Quincke tubes can reduce propagations of fan noise within a duct. Obstructions, such as cylindrical rods, can be placed in the near field of a rotor to generate an anti-phase secondary sound field which can then be tuned to reduce blade tone noise. However, difficulty in tuning the response of these interactions often limits their usefulness. Few passive approaches have demonstrated the ability to reduce blade tone noise locally in the blade region with minimal impact on fan efficiency.
Active noise control approaches have been used for blade tone noise reduction, introducing active secondary sources into the existing sound field of an axial fan. Conventional active approaches have used loudspeaker arrays to reduce levels of fan noise propagating down a duct. Due to the associated weight and non-compactness of loudspeakers, piezoelectric actuators have been used more recently as acoustic transducers imbedded into the stator vanes of axial fans to reduce tonal noise propagations. Air injections, either positioned to generate secondary sources through interaction with the rotor blades or used to improve flow non-uniformities generated by a body in a flow field, have been shown to reduce tonal noise. These approaches have proven effective in a laboratory setting, but are generally prohibitively expensive and potentially unreliable in most actual axial fan applications.
The first known implementation of flow-driven resonator source was to generate a canceling sound field that reduced fan noise generated by a centrifugal blower. More recently, a method of using resonators as flow driven secondary sources has been developed for axial fans. This method behaves as a form of active source cancellation wherein fluid flow interacts with a resonator as a means of generating an acoustic source. A single resonator has been shown to be effective for reducing unidirectional propagations of blade tone noise by as much as 24 dB, while an array of resonators equal to the number of stator vanes was used to reduce propagations of both plane-wave and higher order mode propagations by 28 dB.
A fundamental shortcoming of the single resonator axial fan experiments, particularly for plane wave propagations where fan noise radiates as an axially propagating dipole, is that flow driven resonators respond acoustically as monopole sources. For this reason, only unidirectional propagations of the plane wave mode can be reduced using a single resonator or circumferential array of resonators as shown in FIG. 1. While this results in a reduced noise level in one (in this case, downstream) direction, it also may cause an increased noise level in the other (in this case, upstream) direction.

Dipole flow driven resonators for fan noise mitigation


An ion-beam sputtering apparatus using an insulator target and a method for operating the same which is characterized by interposing a conductor film forming process during the ion beam processings using the insulator target. This conductor film formation prevents undesired charge build up on the inside of the apparatus and prevents undesired occurrence of abnormal discharge in the ion beam processing using an insulator as a target.

1. Field of the Invention
This invention generally relates to an improvement of ion-beam sputtering technology, and more particularly to an improvement of an apparatus and a method for performing a sputter deposition using an insulator as a target.
2. Description of the Related Art
Irradiating ions to bombard a target to cause an elastic or inelastic collision with atoms and molecules of a surface of the target for scattering the atoms/molecules or penetrating the irradiated ions into the target is generally called a sputtering process. Sputtering technology includes ion-beam sputtering, direct-current sputtering, and high-frequency sputtering.
Of these sputtering technologies, ion-beam sputtering employs an apparatus which comprises two chambers, i.e., an ion generating chamber where ion-beams are generated and a processing chamber where etching and/or film-forming or deposition is performed by irradiating the ion beams to the target.
The ion generating chamber is maintained at a low level of vacuum of at most 10.sup.-4 Torr and has on its ion beam emitting side a plurality of electrodes through which the ions are emitted. On the other hand, the processing chamber is kept at a high level of vacuum of about 10.sup.-5 Torr. In the processing chamber, a target and a substrate are arranged in position for processing.
With this ion-beam sputtering apparatus, since the processing chamber is maintained at a high level of vacuum as described above, a high-purity thin film can be obtained. And since no negative bias is applied to the target, as opposed to direct-current sputtering, an insulator can be used as the target.
However, when this conventional ion-beam sputtering apparatus is operated to perform ion-beam sputtering for 10 to 20 hours in total, employing as the target an insulator or a material which reacts with a gas in a high vacuum to produce an insulator, sputtered particles expelled from the target by ion beams adhere to all or part of the processing chamber wall surfaces or to all or part of the surfaces of the electrodes in the ion generating chamber, forming an undesired insulator film thereon.
As a result of this, when the surface of the so formed insulator film is subjected to ion irradiation, ions adhere to the film surface. Because the surfaces to which the ions adhere are insulative, the ions will not easily move. This causes local charges on the surface of the insulator film. Likewise the electrodes of the ion generating chamber are charged.
After the sputtering operation is continued for a long time, for example, for 10 or 20 hours, a potential difference between the locally charged portions and the uncharged portions increases, causing local discharge.
As a result, the ion beams might be curved, and the intensity of the ion beam to be irradiated on the target cannot be constant. This varies the processing conditions. The electrodes of the ion generating chamber are also subjected to a similar phenomenon since the electrodes are also covered with insulator film.
In order to solve this problem, after sputtering for about 10 to 20 hours in total, the high vacuum processing chamber is opened to the atmosphere, the wall surfaces of the processing chamber are cleaned, and the electrodes of the ion generating chamber are dismantled and then cleaned for a further operation.
When the conventional technology is used for effecting sputtering of an insulator substance for a long time of about 10 or more hours in total, the processing conditions such as the ion-beam intensity would vary for the reason as mentioned above, unless the cleaning etc. is carried out from time to time. In an etching operation, for example, the depth of the etching can not be constant.
As mentioned above, in order to make the processing conditions constant, the high vacuum processing chamber is opened to the atmosphere every 10 to 20 hours, and the wall surfaces of the processing chamber are cleaned, and further the electrodes of the ion generating chamber are dismantled and cleaned. This, however, lowers the efficiency of the operation.
Further, when the high vacuum processing chamber is opened to the atmosphere, moisture in the air is absorbed by the insulator film formed on the wall surface of the processing chamber. This absorbed moisture is not readily desorbed from the insulator film even after the processing chamber is evacuated. Thus, there is a fear that moisture will then be incorporated into the desired film.

Ion-beam sputtering apparatus and method for operating the same


In order to realize a semiconductor device which is easily mounted on a circuit board and which has high mounting reliability, a semiconductor device 1 of the present invention includes: a semiconductor substrate 2; and an Au bump 3 provided on an electrode 21. The Au bump 3 is provided with a projection 3a. Also, on a surface of the Au bump 3, a solder layer 32 is formed via a Ni layer 31. The projection 3a makes it possible to easily mount the semiconductor device 1 by applying a small weight. Further, even if the amount of solder 62 supplied on an electrode 61 on a circuit board 6 is reduced, it is possible to bond the semiconductor device with a sufficient amount of solder during mounting. Furthermore, because a Ni layer 31 prevents dissolution of the bump, it is possible to ensure high mounting reliability.

Conventionally, a semiconductor substrate is electrically connected to a circuit board by means of wire bonding. The wire bonding requires to ensure, on the outside of a chip, a space to which an end of a wire is connected. This increases the size of a package. Further, the wire bonding requires a long connection distance between the semiconductor substrate and the circuit board, thereby increasing inductance. For this reason, with the wire-bonding, it is difficult to increase a processing speed of a semiconductor device.
In order to solve these problems, Japanese Unexamined Patent Application Publication, Tokukai, No. 2006-54311 (published on Feb. 23, 2006; hereinafter, referred to as "Patent Document 1") and Japanese Unexamined Patent Application Publication, Tokukaihei, No. 11-87391 (published on Mar. 30, 1999; hereinafter, referred to as "Patent Document 2") propose a flip-chip bonding method. The flip-chip bonding method is such a bonding method that (i) a bump for bonding a semiconductor device to a circuit substrate is formed on a functional surface of the semiconductor substrate, (ii) the functional surface is set so as to face a surface of the circuit substrate, and (iii) the bump is bonded to an electrode on the circuit substrate.
FIG. 12 is a view illustrating a semiconductor device 71 described in Patent Document 1. The semiconductor device 71 includes: a semiconductor substrate 72; an Au bump 73 formed on an electrode 721 of the semiconductor substrate 72 and on a surface protection film 722 of the semiconductor substrate 72; a diffusion-prevention film 74 made of TiW; and a bonding film (solder) 75 formed on the diffusion-prevention film 74. TiW, which is material of the diffusion-prevention film 74, has a low diffusion coefficient for Au, so as to prevent diffusion between the Au bump 73 and Sn, which is material of the bonding film 75. Thus, it is maintained that the bonding film 75 is made of Sn purely.
One example of the flip-chip bonding method which is widely used is Au-solder bonding. The Au-solder bonding is a method for bonding together an Au bump formed on a semiconductor substrate and solder supplied on an electrode on a circuit board. This method utilizes Au—Sn metal bonding. Therefore, this method has high mounting reliability and is available in manufacturing fine-pitch products.
Also, such an arrangement is proposed that an Au bump is provided with a projection for the purpose of facilitating the process of flip-chip bonding. FIG. 13 is a cross-section view illustrating a process in which a semiconductor device 81 is mounted on a circuit board 6. FIG. 13 (a) illustrates a state where the semiconductor device 81 is not mounted on the circuit board 6 yet, and FIG. 13 (b) illustrates a state where the semiconductor device 81 has been mounted on the circuit board 6. The semiconductor device 81 includes: a semiconductor substrate 82; and an Au bump 83 which is provided on an electrode 821 on the semiconductor substrate 82. The Au bump 83 is provided with a projection 83a. An electrode 61 on the circuit board 6 is provided with solder 62.
As illustrated in the mounting structure in FIG. 13 (b), the projection 83a is inserted into the solder 62. This makes it possible to mount the semiconductor device 81 by applying a small weight.
In the arrangement illustrated in FIG. 13, however, the solder 62 is supplied only on the electrode 61 on the circuit board 6. Therefore, this arrangement cannot supply a sufficient amount of solder. As a semiconductor device has a higher density structure and a higher processing speed, the semiconductor device is required to have finer pitch between electrodes for flip-chip bonding, the electrodes being provided on a semiconductor substrate and on a circuit substrate. Having finer pitch between electrodes decreases the amount of solder which can be supplied. Therefore, it is difficult to enhance the mounting reliability in the arrangement illustrated in FIG. 13.
On the other hand, Patent Document 2 proposes an arrangement where solder is supplied, in advance, on an Au bump only.
FIG. 14 is a view illustrating a semiconductor device 91 described in Patent Document 2. The semiconductor device 91 includes: a semiconductor substrate 92 provided with an electrode 921; and an Au bump 93 provided on the electrode 921. Further, the Au bump 93 is provided with a projection 93a having a nose-shape. Also, the Au bump 93 is provided with solder 94 covering the projection 93a. However, Patent Document 2 does not disclose an arrangement where solder is supplied on the circuit substrate side in Therefore, in the arrangement illustrated in FIG. 14 also, it is impossible to ensure a sufficient amount of solder used for mounting a semiconductor device on a circuit board. That is, it is difficult to enhance the mounting reliability in the arrangement illustrated in FIG. 14, as well as in the arrangement illustrated in FIG. 13.
As such, the conventional arrangements described above have such a problem that sufficient mounting reliability cannot be attained.
Specifically, in the semiconductor device 71 described in Patent Document 1, the bonding film 75 is formed only on the top surface of the Au bump 73. Therefore, this arrangement cannot ensure a sufficient amount of solder, thereby decreasing the mounting reliability.
In the semiconductor device 81 illustrated in FIG. 13, as described above, the solder 62 is supplied only on the electrode 61 on the circuit board 6. Therefore, this arrangement cannot supply a sufficient amount of solder. That is, it is difficult to enhance the mounting reliability. Further, in the state illustrated in FIG. 13 (b), there is a case where the solder 62 reaches the electrode 821. If a high-temperature storage test is carried out with such a state, the solder 62 comes in an interface between the Au bump 83 and the electrode 821. This forms an intermetallic compound of Au and Sn, thereby causing a breakage in an early stage.
In the arrangement described in Patent Document 2, the solder 94 is directly supplied on the Au bump 93. This increases the amount of Au which diffuses in the solder 94, thereby leading to dissolution of the bump. Because the projection 93a on the Au bump 93 is thin, the mounting reliability will be significantly decreased if the projection 93a on the Au bump 93 is dissolved. Further, in this case, the solder has already reached the Au bump 93. This further increases the possibility of a breakage caused by the solder which has reached the electrode.
Patent Document 2 does not disclose such an arrangement that solder is supplied also on an electrode on a circuit board for the purpose of mounting a semiconductor device on the circuit board. That is, because the solder is supplied only on the Au bump 93, it is impossible to mount the semiconductor device 91 on the circuit board with a sufficient amount of solder. For this reason, it is impossible to enhance the mounting reliability in the arrangement described in Patent Document 2.
In the semiconductor device 81 illustrated in FIG. 13, the following arrangement is possible: The size of the Au bump 83 is increased so that the Au bump 83 touches the surface protection film 822 and covers the electrode 821 completely. This arrangement prevents the solder 62 from coming in the interface between the Au bump 83 and the electrode 821. However, in this arrangement, bonding pressure generated in the process of forming the Au bump 83 can cause a crack on the surface protection film 822.

Semiconductor device, method for mounting semiconductor device, and mounting structure of semiconductor device


A high-melting-point conductive oxide includes a mixture of a powdered Sr compound and Ru compound and/or Ru metal. The mixture is sintered at a primary temperature of 900xc2x0 C. to 1300xc2x0 C. in an atmosphere containing oxygen to form a sintered body that is pulverized back to a powder. The powder is given a desired shape that is again sintered, this time at a secondary temperature of 1000xc2x0 C. to 1500xc2x0 C. higher than the primary temperature, again in an atmosphere containing oxygen. The high-melting point conductive oxide is used as a heating element for high-temperature use, an electrode material for high-temperature use, a material for high-temperature thermocouple use and a light-emitting material for high-temperature use.

1. Field of the Invention
The present invention relates to a high-melting-point conductive oxide, to a method of manufacturing the oxide, and to a high-temperature electrically conductive material used to form high-temperature heat-generating materials, such as heating elements for generating high temperatures in electric furnaces and the like, electrode material capable of being used at high temperatures, high-temperature light-emitting material including filament material for lamps and the like, and high-temperature thermocouple material and the like, utilizing heat produced when a current is passed through the oxide in an atmosphere containing oxygen.
2. Description of the Prior Art
Electric furnaces that utilize resistance-heating employ a heating element material selected for that purpose. In air or an atmosphere including an oxygen, silicon carbide (SiC) heating elements can be used to obtain temperatures in the order of 1600xc2x0 C., and molybdenum disilicide (MoSi2) heating elements can be used to obtain temperatures up to around 1700xc2x0 C. Platinum (Pt) or platinum-rhodium (Ptxe2x80x94Rh) metal wire has a melting point of 1769xc2x0 C., and can be used for electric furnaces that go up to 1500xc2x0 C. Including the temperature dependency, the electrical resistivity of these heating elements is more or less metal-like. Heating elements of lanthanum-chromite, an oxide of lanthanum and chromium, has a semiconductor-like temperature dependency, but because of the material""s relatively low electrical resistance, can be used to form general-purpose electric furnaces capable of obtaining temperatures of up to 1900xc2x0 C.
To obtain higher temperatures with resistance-heating methods, zirconia (ZrO2) or thoria (ThO2) having a melting point or decomposition temperature of 2000xc2x0 C. or more is used. Since these oxides are semiconductors, current flow can only occur at high temperatures of at least 1000xc2x0 C. That is, since they have to be used in conjunction with other heating elements with metal-like resistivity, general-purpose electric furnaces that use these oxides as heating elements have not yet been realized. In hydrogen or an inert gas or other reducing atmosphere, the high-melting-point metals of molybdenum (Mo), tantalum (Ta) and tungsten (W) can be used to obtain high temperatures of up to 2000, 2100 and 2500xc2x0 C., respectively. In the presence of very small amounts of oxygen (10xe2x88x925 Torr or more), these heating elements readily form oxides, increasing their electrical resistance. For this reason, they cannot be used in an oxygen atmosphere.
Noble metals such as ruthenium (Ru), iridium (Ir) and rhodium (Rh) have high melting points (ruthenium: 2250xc2x0 C.; iridium: 2457xc2x0 C.; rhodium: 1963xc2x0 C.). However, in an oxidizing atmosphere, at high temperatures these metals readily vaporize or oxidize. Moreover, the fact that they are noble metals mean that they are very expensive, costing four or five times more than gold, and they are not easy to machine, all of which makes it very difficult in practice to use them as heating element materials.
JP-A-HEI 6-223960 discloses high-frequency heating elements formed of oxides of ruthenium, iridium, rhodium or other elements. The invention of this disclosure has as its object the use of microwave absorption for heating applications such as microwave ovens and the like, and is characterized in that when the above materials are used to form heating elements for high-frequency heating, the materials exhibit good temperature elevation characteristics. The materials are intended for use at around 600xc2x0 C. to 870xc2x0 C., which is not the same as materials intended to be used at temperatures in the order of 2000xc2x0 C.
Previously, resistance-heating to temperatures of 2000xc2x0 C. or higher has only been possible using heating elements of tungsten or other such high-melting-point metal in a reducing atmosphere of hydrogen or an inert gas or the like. There have not been any suitable materials, that could be used in an oxidizing atmosphere, having a melting point in the order of 2000xc2x0 C. and metal-like electrical resistivity. Therefore, there has not been a practical electric furnace capable of achieving a temperature of 1700xc2x0 C. or higher. In other words, there has been no method of generating a high temperature of at least 1700xc2x0 C. utilizing resistance-heating in an oxidizing atmosphere. Similarly, there has no thermocouple material to measure a temperature of 1700xc2x0 C. or more. However, if there were a material having a metal-like low electrical resistance and a melting point of around 2000xc2x0 C. in an oxidizing atmosphere, it would be possible to provide a method of resistance-heating at a previously unattainable temperature range, and it would also be possible to use a thermocouple to measure such high temperatures.
An object of the present invention is therefore to provide a high-temperature electrically conductive material that can be used for heating elements, electrode material, thermocouple material, light-emitting material and other such materials in an electric furnace that can be used in an oxidizing atmosphere at a high temperature of 1700xc2x0 C. or more.
Another object of the present invention is to provide a high-melting-point electrically conductive oxide constituting the high-temperature electrically conductive material, and a method of manufacturing the same.
To attain the above object, the present invention provides a high-melting-point conductive oxide that is a Srxe2x80x94Ru oxide comprising a mixture of a powdered Sr compound and Ru compound or Ru metal that is sintered at 900xc2x0 C. to 1300xc2x0 C. in an atmosphere containing oxygen to form a sintered body that is pulverized to a powder, shaped and again sintered at 1000xc2x0 C. to 1500xc2x0 C. in an atmosphere containing oxygen.
The above object is also attained by a high-melting-point conductive oxide that is a Srxe2x80x94Ru oxide comprising a mixture of powdered SrCO3 and RuO2 that is sintered at 900xc2x0 C. to 1300xc2x0 C. in air to form a sintered body that is pulverized to a powder, shaped and again sintered at 1000xc2x0 C. to 1500xc2x0 C. in air.
The above object is also attained by a high-melting-point conductive oxide that is a Srxe2x80x94Ru oxide single-crystal comprising a Srxe2x80x94Ru oxide obtained as described above that is melted by concentrated infrared radiation or the like and recrystallized.
The present invention also includes the oxide and oxide single-crystal in which a molar ratio between the SrCO3 and the RuO2 is 2:1.
The above object is also attained by a method of manufacturing the high-melting-point conductive oxide, the method comprising mixing together powdered SrCO3 and RuO2 to form a mixture, sintering the mixture in air at 900xc2x0 C. to 1300xc2x0 C. to form a sintered body, pulverizing the sintered body to a powder, shaping the powder, and sintering the shaped powder in air at 1000xc2x0 C. to 1500xc2x0 C.
The present invention also includes a method of manufacturing the Srxe2x80x94Ru oxide single-crystal by using focused infrared radiation or the like to melt the Srxe2x80x94Ru oxide obtained as described above, and recrystallizing the melted oxide.
The present invention also provides high-temperature heating elements, high-temperature electrode material, light-emitting material and high-temperature thermocouple material comprised of the oxide or single-crystal for use in an atmosphere containing oxygen.
As described in the foregoing, as a material for use as heating elements, electrode material, light-emitting material and thermocouple material, of all the conductive oxides, there is used an oxide or single-crystal containing Sr and Ru, which in an atmosphere containing oxygen has the highest melting point and exhibits metal-like electrical resistance up to temperatures close to the highest melting point. The result is material properties that do not undergo change even at 2000xc2x0 C. and can effect, for the first time, formation of oxidizing atmospheres at 2000xc2x0 C. and measurement of temperatures in oxidizing atmospheres at 2000xc2x0 C.
The above and other objects, further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and following detailed description of the invention.

High-melting-point conductive oxide, method of manufacturing the same, and high-temperature electrically conductive material based on the oxide

National Institute of Advanced Industrial Science and Technology

c/o Electrotechnical Laboratory, Agency of Industrial Science and Technology, 1-4 Umezono 1-chome


A hot-rolled steel sheet for a generator rim contains a structure containing a ferrite phase with an areal ratio of 95% or more in which precipitates containing Ti and V whose average grain diameter is less than 10 nm are precipitated in crystal grains of the ferrite phase. The ferrite phase has an average crystal grain diameter within the range of 2 μm or more and less than 10 μm. The hot-rolled steel sheet for a generator rim has strength with a yield strength YS in a rolling direction of 700 MPa or more and electromagnetic properties with a magnetic flux density B50 of 1.5 T or more and a magnetic flux density B100 of 1.6 T or more.

From the viewpoint of the preservation of the global environment, global warming has been recently regarded as a problem, and it has been desired to reduce carbon dioxide CO2 emissions by such methods as improving the fuel efficiency of automobiles. From such a viewpoint of curbing global warming, hydraulic power generators have been recently reconsidered as a clean energy source. A generator such as the hydraulic power generator includes a rotor and a stator, in which the rotor includes a pole core serving as an iron core and a rim that supports it. In order to gain generating capacity, the rotor is required to be rotated at a high speed. For this purpose, the rim is required to hold high strength in order to resist a centrifugal force caused by the high-speed rotation, and hot-rolled steel sheets having a yield strength of about 550 MPa have been mainly used for the rim. However, it has been recently demanded to use high-strength hot-rolled steel sheets having a yield strength of about 700 MPa or more. The steel sheets for the rim are required to hold excellent magnetic properties at the same time.
In response to such a demand, Patent Literature 1, for example, discloses a hot-rolled steel sheet containing, in terms of percent by weight, C: 0.02% or more and 0.10% or less, Si: 2.0% or less, Mn: 0.5% or more and 2.0% or less, P: 0.08% or less, S: 0.006% or less, N: 0.005% or less, and Al: 0.01% or more and 0.1% or less, contains Ti in an amount of Ti: 0.06% or more and 0.3% or less and 0.50<(Ti-3.43N-1.5S)/4C, and having a microstructure that has an areal ratio of low-temperature transformed products and pearlite of 15% or less, and in which TiC is dispersed in polygonal ferrite. With the technique disclosed in Patent Literature 1, one or more of Nb, Mo, V, Zr, Cr, Ni, Ca, or other elements may be contained in the hot-rolled steel sheet. Although not considering magnetic properties, the technique disclosed in Patent Literature 1 can achieve a hot-rolled steel sheet having remarkably improved stretch flange formability at high strength with a tensile strength TS of 70 kgf/mm2 (690 MPa). However, the technique disclosed in Patent Literature 1 requires a large content of Ti in order to ensure the desired high strength. This makes coarse Ti carbide exceeding 30 nm, which does not contribute to higher strength, likely to be produced. The amount of solute Ti increases. Bainitic ferrite having high dislocation density is likely to be produced, and magnetic properties can degrade accordingly.
Patent Literature 2 discloses a method for manufacturing a high-tensile hot-rolled steel sheet having high magnetic flux density. The technique disclosed in Patent Literature 2 is a method for manufacturing a high-tensile hot-rolled steel sheet including heating a steel slab containing, in terms of percent by weight, C: 0.05% or more and 0.15% or less, Si: 0.50% or less, Mn: 0.70% or more and 2.00% or less, P: 0.020% or less, S: 0.010% or less, sol. Al: 0.010% or more and 0.10% or less, N: 0.0050% or less, Ti: 0.10% or more and 0.30% or less, and B: 0.0015% or more and 0.005% or less to a temperature of 1200° C. or more, performing hot rolling with a hot-rolling finishing temperature within the range of the Ar3 transformation point or more and 950° C. or less, cooling it with a cooling rate within the range of 30° C./s or more and less than 70° C./s, and winding it at 500° C. or less. The technique disclosed in Patent Literature 2 can achieve a high-tensile strength hot-rolled steel sheet having high magnetic flux density with a magnetic flux density B100 of 1.77 T or more with an yield strength YS of 80 kg/mm2 (785 MPa) or more and a tensile strength TS of 100 kg/mm2 (980 MPa) or more. However, the technique disclosed in Patent Literature 2 essentially contains B for the purpose of improving hardenability and performs quenching after hot rolling. This makes a bainite phase likely to be produced, and magnetic properties degrade, leading to insufficient magnetic properties as an iron core of a rotary machine.
Patent Literature 3 discloses a method for manufacturing a high-tensile strength hot-rolled steel sheet having high magnetic flux density. The technique disclosed in Patent Literature 3 is a method for manufacturing a high-tensile strength hot-rolled steel sheet including heating a steel slab containing, in terms of percent by weight, C: 0.02% or more and 0.06% or less, Si: 0.10% or less, Mn: 0.3% or more and 1.2% or less, S: 0.02% or less, Al: 0.10% or less, N: 0.01% or less, and Ti: 0.05% or more and 0.30% or less to a temperature of 1200° C. or more, performing hot rolling with a hot-rolling finishing temperature within the range of the Ar3 transformation point or more and 900° C. or less, and winding it in the temperature range of 500° C. or more and 650° C. or less. The technique disclosed in Patent Literature 3 can achieve a high-tensile strength hot-rolled steel sheet having a tensile strength TS of 50 kg/mm2 (490 MPa) and a magnetic flux density B100 of 1.8 T or more. The technique disclosed in Patent Literature 3 reduces the content of Si to 0.10% or less and ensures desired high strength through precipitation strengthening by Ti carbide. However, the technique disclosed in Patent Literature 3 contains a large amount of Ti, which makes bainitic ferrite having high dislocation density likely to be produced, degrades magnetic properties, and makes it difficult to ensure sufficient magnetic properties as an iron core of a rotary machine.
Patent Literature 4 discloses a hot-rolled steel sheet for an iron core of a rotary machine that contains, in terms of percent by weight, C: 0.10% or less, Si: 0.5% or less, Mn: 0.2% or more and 2% or less, P: 0.06% or less, S: 0.01% or less, Al: 0.1% or less, N: 0.006% or less, and Ti: 0.02% or more and 0.2% or less, further contains at least one of Mo: 0.7% or less (except for the range of 0.2% or less) and W: 0.15% or less, contains carbide smaller than 10 nm containing at least one of Ti, Mo, and W dispersed in a ferrite structure with a volume fraction of 95% or more, and has a strength of about 590 MPa or more. The technique disclosed in Patent Literature 4 can achieve a high-strength hot-rolled steel sheet that has excellent magnetic properties while having excellent formability and has sufficient properties as an iron core of a rotary machine.

This patent is subject to a terminal disclaimer.

Hot-rolled steel sheet for generator rim and method for manufacturing the same