3,3-Dimethylbutyraldehyde is synthesized via hydrolysis of 1,1-dichloro-3,3-dimethylbutane or 1-bromo-1-chloro-3,3-dimethylbutane in the presence of water and a base and is purified via an aldehyde/bisulfite adduct.

1. Field of the Invention
This invention relates to the synthesis and purification of 3,3-dimethylbutyraldehyde via hydrolysis of 1,1-dichloro-3,3-dimethylbutane or 1-bromo-1-chloro-3,3-dimethylbutane with high purity.
2. Related Background Art
A method for synthesizing 3,3-dimethylbutyraldehyde via hydrolysis of 1,1-dichloro-3,3-dimethylbutane at 300.degree. C. with a 60% yield is reported by L. Schmerling J. Am. Chem. Soc., vol. 68, 1946, pp. 1650-1654. This reaction would generate hydrochloric acid but was carried out in a closed system by heating a mixture of water and 1,1-dichloro-3,3-dimethylbutane without addition of a base. It is well known that hydrochloric acid is very corrosive to typical commercial reactors, which are constructed of metal alloys, especially at high temperature and pressure. Such reaction conditions are highly undesirable because they may lead to structural failure of the reactors and may be very hazardous.
A method for synthesizing 3,3-dimethylbutyraldehyde via hydrolysis of 1,1-dichloro-3,3-dimethylbutane at 180.degree.-200.degree. C. is disclosed in Soviet Patent No. 721400. The method disclosed therein comprises heating 1,1-dichloro-3,3-dimethylbutane with water in the presence of catalytic amounts of magnesium oxide or triethylamine, at 180.degree.-200.degree. C. The yield is reported to be 88-90%.
However, repetition of this reported reaction was found to give a significant amount (30-40%) of cis and trans tert-butyl vinyl chloride and 43% of the starting material remained unreacted. This is highly undesirable because the boiling points of 3,3-dimethylbutyraldehyde and tert-butyl vinyl chloride are very close; hence, they can not be separated by distillation techniques.
Purification of aldehydes by their conversion into a solid aldehyde/bisulfite adduct has been described in the literature. "Purification of Laboratory Chemicals" (Pergamon Press, 1988), pages 60-61, is incorporated by reference herein as a general reference for this methodology. Typically, the crude aldehyde is stirred with aqueous sodium bisulfite or sodium bisulfite in a mixture of water and alcohol. The precipitates are isolated, washed with water and/or alcohol, and then converted into free aldehyde with a base or acid.
3,3-Dimethylbutyraldehyde is an intermediate that is useful in the preparation of the sweetener N-[N-(3,3-dimethylbutyl)-L-.alpha.-aspartyl]-L-phenylalanine disclosed in U.S. Pat. No. 5,480,668, U.S. Pat. No. 5,510,508 and U.S. Pat. No. 5,728,862. Thus, despite the techniques for the hydrolysis of 1,1-dichloro-3,3-dimethylbutane described in the prior art, it is clear that there is a need to economically produce 3,3-dimethylbutyraldehyde using more efficient methods than currently available.

Synthesis and purification of 3,3-dimethylbutyraldehyde via hydrolysis of 1,1-dichloro-3,3-dimethylbutane or 1-bromo-1-chloro-3,3-dimethylbutane


A method for determining the relative body temperature of a warm-bodied animal is described. The method, in part, involves an article of manufacture that provides a manifestation, or visually observable indication on an exterior surface, of a relative state of the warm-bodied animal's body temperature, either being too cold or too hot, as a measure against relative levels of hypothermia or hyperthermia, or poor circulation.

Thermo-regulation of mammalian bodies has been of interest for a variety of health and medical applications, as well as general consumer uses. Warm-blooded animals, including human beings, maintain thermal homeostasis. That is, they are able to keep their core body temperature within a normal range, a near constant level, regardless of the ambient temperature of the surrounding environment. This can involve not only the ability to generate heat, but also the ability to prevent being over-heated and to cool down. Body temperature maintenance incorporates a wide range of different techniques that result in a body temperature continuum. For example, typically, warm-blooded animals control their body temperature by regulating their metabolic rates (e.g. increasing their metabolic rate as the surrounding environmental temperature begins to decrease), such as through shivering when the ambient temperature becomes too cold. Additionally, when the body becomes too hot, humans perspire as another several safety features that help to regular the body's normal temperature. If the body is unable to maintain a normal temperature, hyperthermia or the opposite condition, hypothermia, can occur.
Body temperature regulation is an important parameter for patients who undergo surgery or during post operative recovery. Human body temperature can fluctuate temporarily due to various factors, such as age, physical activity, illness, or emotional stress, normal body temperature is 98.6° F. (37° C.) when the body is at rest. Studies have demonstrated that maintenance of a normal or relatively warm patient body temperature during medical procedures can minimize the likelihood of post surgical infections or other complications, and help the patient heal more quickly, thus shorten hospital stays (e.g., Woo Y J, Atluri P, Grand T J, Hsu V M, Cheung A. "Active Thermoregulation Improves Outcome of Off-Pump Coronary Artery Bypass," Asian Cardiovasc. Thorac. Ann. 2005, 13:157:160; Mahoney C B, Odom J. "Maintaining Intra-Operative Normothermia: A Meta-analysis of Outcomes with Costs. AANA J. 1999, 67:155-163). For a healthy human being, normal skin temperature around the body core is about 35° C., and the skin temperature of the arms and legs typically may range from about 31-33° C.
Regulation of an infant's body temperature is another parameter of interest for healthcare professionals, parents, and other caregivers. The normal axillary temperature of a newborn infant may range from about 36 to 37.5° C., after measuring for about 5 minutes. Because neonatal babies typically are not able to regulate their body temperature as well as older children or adults, they easily may become either cold or overheated which can lead to a variety of health problems (hypothermia, heat exhaustion, etc.). Hence, it is not wise to either cover or overdress them on warm days or underdress them on cold days. With such little skin surface, infants lose heat or overheat fast. Premature babies, in particular, are susceptible to temperature fluctuations, and are typically housed in incubators and monitored closely to ensure that they are kept sufficiently warm without overheating. A caregiver would want to know whether the infant was too cold, or at the other extreme a caregiver would wish to be able to monitor the temperature of a feverish infant. A fever temperature of 100.4° F. or greater can be dangerous and should be reported to a doctor. Similarly, the elderly are another population that may be susceptible to difficulty regulating their body temperature, especially with respect to overheating.
A temperature sensitive composition that communicates a relative response by means of a visual indicator can be incorporated into certain protective articles, clothing or garments. Nonwoven fabrics have been treated with thermochromic pigments to provide a visual indication of a shift in temperature through color change. In many cases, the thermochromic pigments are coated onto the fibers or fabric using a multi-step topical application method. However, topical application may lead to color flaws in the surface of the fabric if the coating is not uniformly applied, along with the additional cost of a post-treatment step. Certain attempts have been made to overcome this problem. U.S. Patent Application Publication No. 2003/0087566 to Carlyle, et al., for example, describes a method for uniformly incorporating a thermochromic pigment into a melt-spun fabric by incorporating it into the polymer melt at the time of fiber or filament formation. However, the method of Carlyle, et al. still lacks the desired level of control over the thermochromic characteristics of the resulting fabric in the range of ambient to body temperature.
As such, a need currently exists for an improved method of using a thermochromic material, such as a nonwoven web, fiber, or film in an application for monitoring the relative temperature of a body or its immediate ambient environment. Currently an unmet need exists for a device, method or system that can help caregivers monitor relative body temperature. Such a device or method would be a helpful and appreciated tool for either patient or child care uses.

Method and articles for sensing relative temperature


A long-life bearing steel and a long-life rolling bearing made of the steel are disclosed. In the steel, the number of oxide or oxide-based inclusion particles in a given unit area A of 160 mm.sup.3 with an average particle size of 3 to 30 .mu.m is 80 or less and an abundance of oxide or oxide-base inclusion particles with 10 .mu.m or more average particle size to oxide or oxide-based inclusion particles having an average particle size of 3 to 30 .mu.m is below 2%. An electron beam melting extraction evaluation method irradiating electron beam under the following condition guarantees the cleanness of the steel: 350 V+100.ltoreq.J.ltoreq.700 V+200, wherein J represents electric charge power in W provided by electron beam and V represents a sample volume in cm.sup.3.

1. Field of the Invention
The present invention relates to bearings steels and to long life rolling bearings used in automotive vehicles, agricultural machinery, construction machinery and iron-and-steel machinery and, especially, for use in transmissions and engines.
2. Description the Related Art
Conventionally, it is known that in-steel nonmetal inclusions, especially, oxide or oxide-based inclusions cause an increase, for example, in the incidence of wire breaking in wire drawing and a deterioration of the mechanical characteristics of twisting value, fatigue, etc., of a product.
Therefore, various high clean steels with a low content of in-steel oxygen have been provided. For example, Japanese unexamined patent application publication SHO. 53-76916 discloses a high clean steel, the oxygen content of which is 50 ppm or less.
The quality of steel largely depends on the number and size of nonmetal inclusion particles. Methods of determining the number and size of nonmetal inclusion particles comprises JIS-G0555, ASTM-E45 and an image-processing inclusion inspection system disclosed in Japanese unexamined patent application publication SHO. 63-309844.
Bearing life has a close relationship with the cleanness of a material. Particularly, a rolling contact part which is made of a steel with an oxide or oxide-based nonmetal inclusion (especially Al.sub.2 O.sub.3) and which experiences repeated rolling contact stress may experience the occurrence of microcracks derived from the oxide or oxide-based nonmetal inclusion. This eventually leads to flaking originating from the microcrack so that the life of a rolling bearing which includes the rolling contact part expires.
In increasing bearing life, a selection of the content of in-steel oxygen or an index of inclusion in accordance with ASTM standards or a monitoring and evaluation of the size and manner of oxide or oxide-based inclusion particles present in a bearing steel guarantees the cleanness of a material in order to underlie an evaluation of bearing life.
This cleanness guarantee must require a separation of only the oxide or oxide-based nonmetal inclusion from the matrix of a sample and a monitoring and evaluation of the nonmetal inclusion. For this purpose, there is a prior-art method of monitoring and evaluating the oxide or oxide-based nonmetal inclusion using electron beam melting (see "Iron and Steel", pages 83-90, volume 10 of 75th year in 1989 and the Journal issued May 19, 1987 by the Japan Society for the Promotion of Science, pages 5-1 to 5-14).
This prior-art teaches that an electron beam completely melts a small amount of a sample in a button shape to raise and concentrate the inclusion the top surface of the resulting molten metal. A scanning electron microscope (SEM) or the like monitors and evaluates the configurations, sizes and number of oxide or oxide-based inclusion particles after cooling and solidification.
The prior art fails to specify the ranges of the number and sizes of oxide or oxide-based inclusion particles effective to increase the rolling contact fatigue life of a rolling bearing and the relationship between the bearing life and oxide or oxide-based inclusions for securing a sufficient life of a rolling bearing. On the other hand, only conventional items of cleanness evaluation can, with difficulty, discriminate long and short lives of rolling bearing in a situation in which the bearing steel has recently been required to be high-clean, so that selecting only the conventional items failed to increase the bearing life.
The prior-art electron beam melting method entails a problem in that, since it must completely melt a sample, the electric charge power at the time of electron beam generation is excessive. Controlling amount of melting is difficult when only a portion of the sample is melted. Additionally, an inclusion present in the sample below a determined depth cannot be selectively melted and raised to the top surface of the sample.
This problem is prominent especially in steel used for rolling contact parts. That is, it is known that a macroinclusion present at a position of maximum shearing stress defined by Hertz's theory of elasticity provides one of the main causes of flaking which causes termination of the life of the rolling bearing. The position of maximum shearing stress falls within a few millimeters depth from the rolling contact surface of a rolling contact part made of the rolling contact parts steel. Therefore, the material cleanness guarantee for long bearing life requires a selective separation of only an oxide or oxide-based nonmetal inclusion present within the few millimeters depth from the rolling contact surface and a monitoring and evaluation of the separated inclusion. However, the prior art electron beam melting method fails to melt part of a sample so that it cannot selectively separate and monitor macroinclusions present at the position of maximum shearing stress.
In addition, the solidified surface structure of a sample which has experienced button-shaped melting by an electron beam and then been solidified demonstrates a marked affect in distribution of rafts after solidification. This is particularly true when the solidification of the sample produces a dendritic structure on the top surface of the sample. In such instances dendrite arms or branches of the dendritic structure entrap the rafts therebetween in a non-uniform distribution which blocks the SEM or the like from monitoring and evaluating inclusions in the sample. The above problems in the electron beam melting method reduce the accuracy of the life guarantee for the rolling bearing.
A primary object of the present invention is to provide long-life bearing steel or rolling bearings by means of considering oxide or oxide-based nonmetal inclusion particles as an evaluation item for bearing life and controlling the size and number of the inclusion particles.
Another object of the present invention is to provide a long life bearing steel, the bearing life of which is guaranteed by an electron beam melting method of high accuracy capable of monitoring and evaluation of oxide or oxide-based nonmetal inclusions.

Bearing steel and rolling bearing made thereof


Thermally split zirconium silicate is produced such that the crystalline zirconium dioxide embedded in an amorphous silica phase exhibits an average grain or particle size (d.sub.50 value) in a range of 0.5 .mu.m to 3.0 .mu.m and a specific surface area (BET) in a range of 3 to 15 m.sup.2 /g when the silica is removed by leaching. The zirconium dioxide produced by this method is particularly suited for the production of zirconium silicate pigments with improved color characteristics. The thermally split zirconium silicate is also particularly well suited for processes used in the obtention of zirconium dioxide. The method of producing the thermally split zirconium silicate includes melting zirconium silicate in an induction melting furnace and cooling off a free falling stream of melt by blowing on it with a gas and/or spraying it with water.

The invention is relative to thermally split zirconium silicate in which amorphous silica phase monoclinic zirconium dioxide crystals, with a defined grain distribution and specific surface, are embedded. Further subject matter of the invention is constituted by the production of this thermally split zirconium silicate and by its use.
Zirconium dioxide (ZrO.sub.2) in the form of naturally occurring baddeleyite or of synthetically produced products is an important raw material in the production of zirconium dioxide ceramics and zirconium silicate pigments. Zirconium dioxide can be obtained by means of chemical decomposition with subsequent hydrolysis of the zirconates obtained at first or by means of the thermal splitting of zirconium silicate (ZrSiO.sub.4) with subsequent separation of the silica. The thermal splitting of zirconium silicate takes place at temperatures above approximately 1700.degree. C.--W. C. Butterman et al., Amer. Mineralogist 52 (1967). At approximately 1760.degree. C., ZrSiO.sub.4 begins to decompose into tetragonal, solid ZrO.sub.2 and liquid SiO.sub.2. Above approximately 2400.degree. C., ZrO.sub.2 and SiO.sub.2 form a uniform liquid which solidifies by means of rapid cooling off--the thermally split zirconium silicate obtained in this manner is an amorphous silica phase in which zirconium dioxide crystals are embedded such that they can be separated by flotation methods and/or leaching methods from the SiO.sub.2 phase.
Thermally split zirconium silicate, that is, ZrO.sub.2 crystals in an amorphous SiO.sub.2 matrix, like those which were known in the past and which have in part found entry into the market, can be obtained in various types of arc methods and plasma methods.
In the plasma methods, for example Great Britain Patent No. 1,248,595 and Ceramics, February 1974, p. 30, a curtain of zirconium sand is allowed to trickle through the flame of the plasma burner, during which the zirconium silicate is thermally split and then cooled off. A complete splitting of the ZrSiO.sub.4 requires the use of extremely finely ground zircon powder; a grinding of the zirconium sand is energy-intensive and, in addition, foreign substances from the powder aggregate are entrained. The products obtainable in the plasma method contain ZrO.sub.2 crystals with a diameter of 0.1 to 0.2 .mu.m and a length of many .mu.ms (see Great Britain Patent No. 1,447,276). The crystals obtained by the plasma method exhibit a different morphology than that of the products in accordance with the present invention.
According to another method, zirconium silicate is melted in an arc and allowed to solidify as a block, the melted body subsequently is broken and ground ((see Gmelin's Handbuch der anorganischen Chemie (Gmelin's Handbook of Inorganic Chemistry), Zirconium, volume 42 (1958), p. 56)). The thermally split zirconium silicate produced in this manner contains zirconium dioxide with an average grain size (d.sub.50 value) of approximately 15 to 20 .mu.m and a BET surface of approximately 0.5 m.sup.2 /g.
Alternatively, the melt can also be removed from an arc melting furnace and converted into a spherical product by means of cooling off in air, as shown in German patent 26 35 030. The applicant of the present invention determined that the grain distribution of the zirconium dioxide in a thermally split zirconium silicate produced in this manner results in an average grain diameter--d.sub.50 value, determined by laser diffraction--of over 3 .mu.m and in a specific surface according to BET of approximately 2 m.sup.2 /g. The determination of substance data took place here, as in the other instances, on zirconium dioxide obtained by leaching out the thermally split zirconium silicate with concentrated sodium hydroxide solution to a residual SiO.sub.2 content of below 0.5% by weight.
German Patent No. 21 43 526 and Great Britain Patent No. 1,447,276 teach that thermally split zirconium silicate is suitable as raw material for ceramic pigments based on zirconium silicate, e.g. inclusion pigments (e.g. zirconium-iron-rose) and pigments of the host lattice type (e.g. zirconium-vanadium-blue and zirconium-praseodymium yellow). It turned out that the increased requirements as regards color intensity and in part also the location of the color are no longer met by the previously accessible, thermally split zirconium silicate pigments. In order to increase the economy of the decorative design of ceramic articles and/or to obtain more brilliant color tones, the technical field is extremely interested in producing more color-intensive pigments. A starting point for the attainment of this goal is to find more suitable raw materials as the source for zirconium dioxide.
The present invention therefore is directed at solving the problem of providing novel, thermally split zirconium silicates which are more suitable as a source for zirconium dioxide in the production of the industries' more extracting zirconium silicate based pigments (i.e., thermally split zirconium silicates which permit more color-intensive pigments to be produced than the previously known thermally split zirconium silicates).
Thermally split zirconium silicate produced by the method of the present invention is characterized in that the zirconium dioxide embedded in an amorphous silica phase exhibits an average grain size (d.sub.50 value) in a range of 0.5 .mu.m to 3.0 .mu.m and a specific surface (BET) in a range of 3 to 15 m.sup.2 /g. The zirconium dioxide exhibits, as is apparent from the scanning electron microscope photograph of FIG. 3, a typical morphology which could be designated as dendrite-shaped.
Preferred products of the present invention exhibit d.sub.50 values in a range of 5 m.sup.2 /g to 12 m.sup.2 /g for the zirconium dioxide embedded in the SiO.sub.2 phase. Especially preferred products are distinguished by a very narrow grain spectrum of the zirconium dioxide and illustrated by the fact that at least 90% of the zirconium dioxide consists of particles with a diameter less than 10 .mu.m, especially less than 5 .mu.m and greater than 0.2 .mu.m. The grain distribution, including the d.sub.50 value, was determined by means of laser diffraction with water as the suspension liquid, sodium pyrophosphate as dispersing agent and 5 minutes ultrasound mixing in an HR 850 granulometer of the Cilas-Alcatel company. The BET surface was determined with nitrogen as adsorption gas in accordance with DIN 66131. The material characteristics were determined for zirconium dioxide obtained by leaching with concentrated sodium hydroxide solution.
The thermally split zirconium silicates of the invention differ, as explained above, in their material characteristics from those of previously known products. Previously known thermally split zirconium silicates, like those which have previously gained favor in the production of pigments, exhibit higher d.sub.50 values and, in addition, a lesser BET surface. In contrast to the previously known products, zirconium silicate pigments of the host lattice type and inclusion type can be produced by the novel method of the present invention so as to have greater color intensity and a shifting of the particular color location in the desired direction along the color spectrum. Of the zirconium silicate pigments of the host lattice type, there is known pigments in particular in which the Z.sup.4+ positions in the lattice are occupied in a valently compensated manner by chromophoric ions such as vanadium-(blue), praseodymium-(yellow) or terbium ions (yellow) (see U.S. Pat. No. 2,441,447; Great Britain Patent No. 1,447,276; and prospectus 2/83, No. 59 of the Th. Goldschmidt Company). Of the pigments of the inclusion type, there is known pigments in particular in which the color-bearing component such as e.g. cadmium sulfoselenides, iron oxides, iron titanates, colloidal metals and iron-manganese compounds are inclosed in a casing of zirconium silicate (see German Patent No. 23 13 535; German Patent No. 23 23 770; German Patent No. 21 43 525; German-OS Patent No. 39 06 818; and European Patent No. 0,294,664). The advantageous effect, which could not have been foreseen, which the thermally split zirconium silicates of the present invention exert on the pigments follows from examples 2,3 and reference examples 2,3.
A further use of the products of the invention consists in the obtaining of the monoclinic zirconium dioxide contained in the thermally split zirconium silicate by means of known leaching methods. Among the known leaching methods, the one which uses concentrated alkali lyes, especially 30-50% by weight sodium hydroxide solution, are to be emphasized. The thermally split zirconium silicate is treated to this end once or repeatedly with the lye at in general 100.degree. to 200.degree. C., especially 115.degree. to 170.degree. C. under atmospheric or increased pressure and supplied to a solid-liquid phase separation. The leaching can be carried out isothermally or isobarically. At least 2 moles of alkali hydroxide, relative to one mole of the SiO.sub.2 contained in the thermally split zirconium silicate, are used. The duration of the leaching, which is generally between 1 and 10 hours, is a function of the temperature, the lye concentration and the grain size of the thermally split zirconium silicate used. Zirconium dioxides with an SiO.sub.2 content below 0.5% by weight are obtainable in this manner.
It was found that the thermally split zirconium silicate of the invention can be produced by means of inductively melting zirconium silicate in a high-frequency or medium-frequency induction furnace, for example, a coreless induction furnace, with a sintering crust crucible at a temperature in a range of 2500.degree. to 3000.degree. C. and by a subsequent quenching of the melt. The method is characterized in that the melt is drawn off in the form of a stream, this stream is fanned out in a free fall by blowing on it with an inert, cool gas and/or by spraying it with water and quenching the melt thereby and comminuting the product obtained in this manner as required in a breaking and/or grinding manner.
It is advantageous if a thin molten stream with a width of especially 5-20 mm is drawn off via a channel member extending off from the crucible and if compressed air is blown on it with one or several nozzles. In general, the gas used should be at room temperature but higher or lower temperatures are also possible. Alternatively, the melt is sprayed, also while in free fall, with water from one or several nozzles. According to an especially preferred embodiment, air is first blown on the molten stream and then, while it is still in a free fall, water is sprayed on it, prefereably from two or more optionally adjustable, superposed nozzles. In order to quench the drawn-off melt, an amount of air in the range of 0.1 to 3 Nm.sup.3 air per kg melt is generally sufficient. For the quenching by spraying with water, an amount of water in a range of 10 to 100 l per kg melt has proven to be suitable. The product, which has now solidified, can be further cooled, to the extent necessary, in a water basin or a water groove. The product precipitates in the form of granules with a length of approximately 1 m to 10 mm and can be dried and broken as required in a known manner and/or be ground dry or wet to the desired degree of grinding.
The manner of quenching is decisive for the material characteristics of the thermally split zirconium silicate and of the zirconium dioxide contained in it. A slow cooling off of the melt results in larger ZrO.sub.2 crystals which entail the above-described disadvantages in the production of pigments. A simple pouring of the melt into water yields products with a very broad grain spectrum, which is disadvantageous for the formation of pigments and which is outside of the claimed range.
In order to melt the zirconium silicate for thermal splitting, those furnaces that are potential candidates are those in which a uniform melt can be produced and drawn off in the form of a thin stream. The melting can be effected e.g. by means of an arc or by inductive heating. An induction melting furnace with sintering crust crucible like that known from European Patent No. 0,119,877 is very well suited.
Zirconium silicate is cited by way of example in European Patent No. 0,119,877 as a material to be melted; however, there are no suggestions about the thermal splitting and the manner of how melt should be uniformly removed and quenched. According to an embodiment of European Patent No. 0,119,877, the furnace comprises an optionally cooled tube exiting laterally through the wire coil which tube is intended to serve for the removal of the melt; the melt is allowed to run out into a water basin. In the case of a melt of thermally split zirconium silicate, an increase in volume occurs during the cooling off, so that the flow-off tube becomes clogged: An opening of the run-off tube with chiseling and boring tools proved to be unsatisfactory on account of the hardness and brittleness of the solidified melt.
In order for the method to succeed, it is essential that a uniform stream of melt can be removed from the furnace and supplied to the quenching device. This succeeds if the method is carried in a semi-continuous manner in an induction melting furnace with internal wall provided by a melting inductor coil structure which encases a sintering crust crucible. A part of the melt, preferably 5 to 30% of the crucible contents, is removed at periodic intervals and an appropriate amount (e.g. an amount which when melted equals the amount discharged) of zirconium silicate is supplied to the crucible. An open run-out channel, which is located at the upper edge of the inductor coil structure and is intensively cooled, is used as the run-out device. The melt run-out is started at periodic intervals by broaching the melt with a broaching device and the run-out amount is regulated as required by regulated tipping of the furnace with a tipping device. The broaching device comprises a broaching lance and automatically controllable devices for varying the angle of inclination of the lance or for a vertical parallel shifting of the broaching lance, which is positioned horizontally or at an incline, and for extending and retracting the lance. The broaching lance is guided in such a manner that it first catches below the melt nose of the solidified melt from the preceding melt broaching remaining in the run-out channel and the lance is then raised so as to lift the nose and adjacent solidified material. The lance is subsequently driven forward between the raised, solidified melt and the bottom of the channel until the sintered crust formed in the inlet area of the channel is pierced.

Thermally split zirconium silicate, method of its production and use


Disclosed is a light-emitting diode (LED) lighting apparatus having a multifunctional heat sink flange, which includes an LED board on which a transmitted light cap and a plurality of LEDs are mounted, a main heat sink formed of magnesium or an magnesium alloy, an auxiliary heat sink formed of a conductive/polymeric resin material for heat dissipation, a heat sink upper case formed of a conductive/polymeric resin material for heat dissipation, and a power supply. The main heat sink includes multiple streamlined heat sink segments that are integrally formed on an outer surface thereof so as to radially protrude to allow air to flow in all directions, and a heat sink flange formed along an outer circumference of a bottom thereof such that omega-shaped wings having enclosed holes and inverse omega-shaped open holes are alternately formed.

Field of the Invention
The present invention relates, in general, to a light-emitting diode (LED) lighting apparatus having a multifunctional heat sink flange, and, more particularly, to an LED lighting apparatus having an electric lamp type device or a modular type device, in which: a heat sink flange is further formed along an outer circumference of the bottom of a main heat sink to which a LED board is directly fixed such that omega-shaped wings having enclosed holes and approximately inverse omega-shaped open holes are alternately formed as means for widening a heat dissipation area of the main heat sink; heat sink segments formed in various shapes such as a rod shape and a heat sink ring separately formed in various shapes such as a cylindrical shape can be removably installed in correspondence with a change in amount of heat generated from the LEDs installed on the LED board; and various structures (e.g., when the LED lighting apparatus is used as an explosion proof lamp, ornaments including a protective cage; an anti-dropping gadget; lighting apparatus fixing bolts; a lighting color presentation plate; a shock damage-proof cap; a post; or a reflector shade having various shapes) can be installed and used at need in correspondence with a place or a position at which the LED lighting apparatus is installed and a function of the LED lighting apparatus.
Description of the Related Art
Conventionally, lighting lamps widely used in common houses or offices include incandescent or fluorescent electric lamps. Such incandescent or fluorescent electric lamps have high power consumption, waste resources, obstruct environmental protection, and increase an environmental temperature to negatively influence the lamp's service time due to the easy generation of heat.
Thus, lamps using light-emitting diodes (LEDs) which are economical due to low power consumption and a possibility to be made small and are capable of maximizing a lighting effect due to various lighting rays and high visibility have been recently developed and used widely.
Here, LED refers to a photoelectric conversion semiconductor device having a structure in which n-type semiconductor crystals having electrons as majority carriers and p-type semiconductor crystals having holes as majority carriers are joined, and particularly a semiconductor light-emitting element using spontaneous emission light occurring when the electrons and holes injected into the p-n junction are recombined.
Due to high photoelectric conversion efficiency, the LED has very low power consumption and a resultant low generation of heat. Further, since the LED does not emit light based on thermal discharge, the LED does not require a preheating time, and thus are rapidly turned on or off.
Further, since the LED has neither a gas nor a filament, the LED resists a shock and is safe. Since the LED employs a stable direct current lighting-up mode, the LED has low power consumption, enables highly frequent pulse operation, is able to reduce visual fatigue, provides a semi-permanent service time, and is able to produce a lighting effect of various colors. As LED lighting lamps use a small light source, they can be made small.
However, the LED has a problem in that heat generated when an LED chip is driven exerts an influence on brightness and service time.
In a conventional design mainly used to overcome the problem with the generation of heat, a lamp case is formed of an aluminum alloy, and heat dissipation fins are integrally formed on an outer circumferential surface of the lamp case so as to improve a heat dissipation effect. However, the heat dissipation effect can be restrictively produced, which cannot be said to be preferable.
In detail, the conventional LED lighting lamps have a structure in which, when a case and heat dissipation fins are formed of an aluminum alloy, the aluminum alloy is pressed under high pressure using a die for die casting, and the heat dissipation fins formed to smoothly radiate heat generated when LEDs are driven are integrally formed on an outer circumferential surface of the case.
When a main body of the case integrated with the heat dissipation fins is formed using the die for die casting, the aluminum case main body and heat dissipation fins cannot be formed to be thin. As such, it is impossible to reduce weight of a product and to maximize a heat dissipation area. Further, the heat generated when the LEDs are driven cannot be effectively radiated. When the case is formed of the aluminum alloy using the die for die casting, electric wire holes and threaded holes should be formed by post processing. Productivity of products is reduced, and material expenses and production cost of the product are increased. Further, the heat dissipation fins are integrally formed at the same volume, and thus an internal space is reduced. As a result, it is very difficult to form a boss for detachably installing an upper cover or a transparent cap in the narrow space.
Thus, in some of recently proposed techniques, when the case of the LED lighting lamp is formed, a main body having a cylindrical shape is formed by extrusion, and multiple heat dissipation fins coupled to the main body and a disc-like cap to which the heat dissipation fins are radially coupled are formed by cutting and bending a thin steel sheet using a press. Thereby, the heat dissipation area of the heat dissipation fins that are fixedly installed on the main body is increased. In this case, the heat generated from the LEDs can be effectively radiated compared to the main body formed of aluminum.
However, in all the LED lighting lamps, the main body and the heat dissipation fins that are integrally formed or separately installed are formed of a metal. As such, there is a limitation in a reduction in weight. Further, when a short circuit occurs between a power supply for supplying power to the LEDs and the metallic main body, there is a possibility of electric shock.
Thus, to resolve this problem with insulation, in some cases, the power supply itself is formed in an expensive insulation type device. This leads to increasing a production cost of products. In other cases, a heat sink of the main body is covered with insulating paint. This also increases the production cost. Due to the insulating paint, the heat dissipation effect is significantly reduced.
To resolve the above problems, the applicant of the present invention has developed an "LED lighting module for improving heat dissipation and light efficiency," which is disclosed in Korean Unexamined Patent Application No. 10-2012-0087063.
The disclosed LED lighting module is a lighting module using LEDs having low heat generation, low power consumption, and high brightness as a light source. A heat sink for dissipating heat generated from the lighting module is injection-molded using a carbon nanotube metal polymer (CMP) that is a conductive/polymeric heat dissipation resin material containing carbon nanotubes (CNTs) having very excellent heat conductivity such that multiple streamlined heat dissipation rods provide a flow of air in all directions. If necessary, the heat sink is formed by insert injection molding such that an auxiliary heat dissipation plate formed of copper or aluminum having high heat conductivity is integrally formed on the bottom of the heat sink that is in direct contact with a LED board. Further, an upper case in which a power supply is installed is also formed of the CMP.
Thus, the LED lighting module can increase performance of dissipating heat generated from the power supply and the LEDs compared to a conventional lighting module, improve light efficiency of the LEDs, and reduce weight and size of a product itself and reduce production cost as well.
However, despite that the amount of generated heat is different depending on the number of LEDs installed on the LED board, the heat sink used for most of the conventional lighting modules including the lighting module having the aforementioned configuration and conventional lighting apparatuses is not provided with any structure capable of changing a critical capacity of dissipated heat according to the number of installed LEDs, i.e. does never provide changeability of the amount of generated heat with respect to different lighting capacities as well as compatibility of the heat sink itself. The lighting module and apparatus having various lighting capacities cannot be provided using the heat sink having the same shape and configuration.
Conventionally, the heat sinks having different shapes and configurations according to the respective lighting capacities and required capacity of dissipated heat should be separately formed, and multiple lighting modules and apparatuses having different lighting capacities and amounts of generated heat, the same external form, and different volumes should be manufactured. As such, the production cost of a product is increased.
Further, various lighting apparatuses manufactured using the LEDs are required to further install various structures according to an installed place or position or a use purpose, or to be coupled with another structure using such a structure. Among the conventional lighting apparatuses using the LEDs, some have a configuration allowed to be coupled with or installed on a specific structure only. However, no configuration capable of being selectively coupled with the structure regardless of the shape or purpose of the structure when used is provided.

Light-emitting diode lighting apparatus having multifunctional heat sink flange


At the time of polishing an air bearing surface 12 the edge of the air bearing surface 12 is simultaneously beveled to form edge surfaces 14. The air bearing surface 12 is preferably constituted as a flat planar surface 121 having a tapered surface 122 continuous therewith at the air inflow end. In this case, defining the bevel width in regions IV located at the edge surfaces 14 at opposite sides in a direction perpendicular to the air inflow direction and extending in the vicinity of a ridge portion 131 between the central flat planar surface 121 and the tapered inflow end surface 122 and the bevel width in regions II located ahead of an interface 171 between the slider 1 and a thin-film transducer element 17 as I.sub.4 and I.sub.2 respectively, the bevel width of an air inflow end edge surface 14 (region V) continuous with the tapered inflow end surface 122 as I.sub.5 and the bevel width of opposite side edge surfaces 14 (region III) continuous with the central flat planar surface 121 as I.sub.3, (I.sub.4 -I.sub.5)/I.sub.5 is restricted to not more than 0.4, (I.sub.3 -I.sub.2)/I.sub.3 is restricted to not more than 0.2, the bevel width of all edge surfaces 14 is restricted to 4-20 .mu.m, or the bevel width range R thereof is restricted to not more than 5 .mu.m. By in this way restricting the bevel width of the edge surfaces 14 over the entire perimeter of the air bearing surface 12 so as to be highly uniform, there are realized marked improvements in flying stability, particularly a reduction in the variation in roll angle in the flying attitude.

1. Field of the Invention
This invention relates to a thin-film magnetic head.
2. Background Art
Increases in data recording capacity, faster access speeds and the like have been accompanied by rising demand for a thin-film head that has a higher permeability than the ferrite head and is able to maintain a high electromagnetic conversion efficiency even at high transfer rates. Thin-film magnetic heads require various ceramic substrate materials as sliders, and as the material for sliders there are used SiC, ZrO.sub.2, Al.sub.2 O.sub.3, Al.sub.2 O.sub.3 -TiC and the like.
For obtaining a thin-film head slider with stable flying characteristics and good running durability it is necessary to polish the medium-facing surface which constitutes the air bearing surface. As disclosed for example in Japanese Patent Public Disclosure Nos. Sho 60-185272, Sho 63-70918, Hei 2-199614, Hei 2-212057, Hei 2-301014 and the like, at the time of polishing the air bearing surfaces of the slider there is used a polishing film or a polishing tape.
On the other hand, from the point of improving running durability, it is preferable to bevel the edges (ridge portion) at the entire perimeter of the air bearing surfaces. This beveling is ordinarily conducted simultaneously with the polishing of the air bearing surface. Therefore, the size of the bevel differs variously with the surface polishing conditions. However, the aforesaid publications take no notice of, and are totally silent regarding, the dimensional precision of the beveled surfaces (edge surfaces) of the edges.
It has been found that when the air bearing surface(s), e.g. rail surfaces, are polished using a polishing film, since, under ordinary conditions, the amount of beveling conducted at the same time is slight, large variation in bevel size arises between different edge portions. The conventional slider having this variation in bevel size has not been satisfactory in the point of flying stability. More specifically, it has been found that flying instability is produced at CSS (Contact.multidot.Start.multidot.Stop), with increased roll angle variation in the flying attitude. It has further been found that it becomes impossible to secure flying characteristics when the degree of floating is increased.
The main object of this invention is to provide a thin-film magnetic head exhibiting stable flying characteristics, this being achieved by conducting the small amount of beveling conducted simultaneously with surface polishing with high precision.


The present invention is related to a system and method of inspecting a weld. The weld to be inspected is subjected to a transient sonic excitation while the weld area is monitored using a remote infrared camera. The sonic excitation induces mechanical vibration, which causes heat generation at any cracks or other anomalies in the weld. The infrared camera detects any temperature differentials in the weld, indicating the presence of an anomaly. The system and method is particularly useful for welds in environments that are unsafe for extended human presence or that are crowded or otherwise inaccessible, such as with piping or other structural components.

1. Field of the Invention
The present invention relates to the inspection of welds using vibrothermography, and, more particularly, the present invention relates to inspecting and determining the quality of J-groove welds of a nuclear reactor pressure vessel (RPV) head and the RPV bottom mounted nozzles (BMNs) using vibrothermography.
2. Description of the Related Art
Nuclear reactors have a reactor cover or closure head through which a series of openings having tubes extending therethrough to the inside surface of the reactor are welded to the closure head by J-groove welds. These tubes have control rod drives and instrumentation packages sealably extending into the reactor internals. Similarly, the bottom portion of the RPV contains penetrations with instrumentation packages that are also connected to the RPV via J-groove welds.
Certain parts of the reactor vessel head are known to be susceptible to stress corrosion cracking. Many reactor heads have been completely replaced well before the planned design life because of extensive cracking in the nozzles and/or J-groove welds. The J-groove welds must be inspected during reactor shut down for any cracks that may have developed in the welds. Such inspections are usually made from beneath the reactor head with the head on a supporting head-stand during normal refueling periods. J-groove welds are difficult to inspect due to the complex geometry and high radiation fields under the head. Visual techniques are known to have difficulty with very small, tight surface cracks, especially on rough surfaces or after certain processes (i.e., grinding are used to improve surface finish for inspection. Standard nondestructive examination techniques such as eddy current and dye-penetrant examinations are the typical inspection approach used; however, application of these techniques is time-consuming in an operational environment where delays associated with inspections are undesirable. If ultrasound techniques are used for an RPV head inspection, the water couplant must be managed and disposed of following the inspection. Dye-penetrant techniques also suffer from disadvantages including requirements for cleaning the surface, a process that can involve significant volumes of solvent and chemicals.
High radiation under the reactor head makes it undesirable for personnel to perform these inspections by direct contact with the components; thus, various robotic elements are used to remotely access these welds with the mentioned nondestructive testing machinery. The robotic challenges with these techniques are significant, typically requiring a close proximity or actual contact to the tested weld surface which is difficult to achieve with the robotic delivery devices and the remotely controlled tools used to access the welds.
Thus, some form of nondestructive remote inspection of J-groove welds that did not require close proximity or contact with the welded surface, nor the exact robotic manipulation associated therewith (which is difficult to implement), was needed. One such form of testing is described in U.S. Pat. No. 6,856,662, the disclosure of which is incorporated herein by reference. This patent describes a photothermal inspection method, which includes sequentially heating small areas of a weld using a laser while monitoring the weld area using a remote infrared camera. The laser and camera are positioned at an angle of approximately 45° to the inspection surface normal. At cracks or other anomalies (referred to herein collectively as cracks), the thermal wave imparted by the laser does not propagate as rapidly, thereby producing an indication of the crack as a sharp drop in the thermal scan at the point of the crack. The temperature differential is detected using the infrared camera.
While the photothermal inspection method of the '662 patent is an improvement over prior J-groove weld inspection methods, it is desirable to use a nondestructive inspection system and method that allows for a quicker inspection.


A control device configured for mounting within an enclosure having a thermally conductive surface is disclosed. The control device includes a housing, a heat-generating device disposed within the housing, and a thermal conductor. The thermal conductor has a first portion in thermal communication with the heat-generating device and a second portion configured to be in thermal communication with the thermally conductive surface of the enclosure.

The present invention relates generally to control electronic devices, and more particularly to intelligent industrial control devices such as Programmable Logic Controllers (PLCs).
PLCs generally consist of a system power supply, Input/Output (I/O) interfaces, and an intelligent control section that may or may not contain a microprocessor. Some PLCs may be modular in design, such that the control, power supply, and I/O sections, and sometimes the interconnect between these sections, are all separate physical modules that may be interchanged. Some PLCs include electromechanical cooling devices, such as fans or liquid cooling systems for example, to transfer heat away from the heat-generating electronic components enclosed therein. However, some customers that purchase PLCs may prefer not to have such electromechanical cooling devices in their PLC systems for various reasons. These reasons may include, but are not limited to, concerns about the reliability of the cooling device, required regularly scheduled maintenance to clean or replace filters of the cooling device, required regularly scheduled maintenance to lubricate various mechanical components of the cooling device, and concerns relating to excessive heat generation in the event of a malfunctioning cooling device. Electronic components, including those found in PLC systems, generate heat and have manufacturer-dictated ratings on how hot the components may become. The need to remove heat from the PLC and the customer requirement of not using an electromechanical cooling device places limitations on how much heat the PLC components may generate, how high the ambient temperature is allowed to be in the PLC's operating environment, how physically small the PLC modules may be, and thus how much performance and what available features the PLC is capable of delivering.
Accordingly, there is a need in the art for electronic control devices, and particularly PLCs, having a heat transfer arrangement that overcomes these drawbacks.

Apparatus and method for transferring heat from control devices


A semiconductor laser device having high performance, low operating voltage, and long service life, and a method for fabricating the same are provided. A semiconductor multilayer film including an active layer for use of laser beam oscillation is stacked on a substrate. Then a clad layer composed of p-type AlGaAs doped with a p-type impurity Mg, and a contact layer composed of p-type GaAs doped also with Mg are grown by an LPE growth process, and further a surface layer having a high-resistance portion present in the contact layer and low in carrier concentration is removed. The active layer for use of laser beam oscillation is arranged in a substantially center of an end surface from which the laser beam is emitted.

1. Field of the Invention
The present invention relates to a semiconductor laser device to be used in minidisc players and the like, and a method for fabricating the same. More specifically, the present invention relates to a semiconductor laser device having high performance, low operating voltage, and long service life, and also to a method for fabricating the same.
2. Description of the Prior Art
A conventional semiconductor laser device 101 is constructed in the following way, as shown in FIG. 7. A semiconductor multilayer film 108 is stacked on a substrate 102 composed of, for example, n-type GaAs, the semiconductor multilayer film 108 being comprised of a buffer layer 103 composed of Se-doped n-type GaAs, a lower clad layer 104 composed of Se-doped n-type Al.sub.0.5 Ga.sub.0.5 As, an active layer 105 composed of Al.sub.0.13 Ga.sub.0.87 As, an upper clad layer 106 composed of Zn-doped p-type Al.sub.0.5 Ga.sub.0.5 As, and a current blocking layer 107 composed of Se-doped n-type AlGaAs. Further thereon stacked are a clad layer 109 composed of Zn-doped p-type Al.sub.0.5 Ga.sub.0.5 As and a contact layer 110 composed of Zn-doped p-type GaAs, one by one. On top and bottom surfaces of the semiconductor laser device, formed are a p (positive) electrode 111 and an n (negative) electrode 112 composed of, for example, Au--Ge and Au--Zn.
The method for fabricating the above semiconductor laser device is shown in FIGS. 8A, 8B, 8C, and 8D. First, as shown in FIG. 8A, a semiconductor multilayer film 108 is grown one layer after another by an MOCVD (Metal Organic Chemical Vapor Deposition) process on a wafer substrate 102a composed of, for example, n-type GaAs, the semiconductor multilayer film 108 comprising a buffer layer (thickness 2 .mu.m) 103 composed of Se-doped n-type GaAs, a lower clad layer (thickness 1 .mu.m) 104 composed of Se-doped n-type Al.sub.0.5 Ga.sub.0.5 As, an active layer (thickness 0.08 .mu.m) 105 composed of Al.sub.0.13 Ga.sub.0.87 As, an upper clad layer (thickness 0.3 .mu.m) 106 composed of Zn-doped p-type Al.sub.0.5 Ga.sub.0.5 As, and a current blocking layer (thickness 1 .mu.m) 107 composed of Se-doped n-type AlGaAs. Thereafter, as shown in FIG. 8B, a striped groove (top width approx. 4 .mu.m) 113 is formed by etching so as to be bored through the current blocking layer 107.
Further thereon, as shown in FIG. 8C, a clad layer (thickness inside the striped groove 2 .mu.m, thickness outside 1 .mu.m) 109 composed of Zn-doped p-type Al.sub.0.5 Ga.sub.0.5 As and a contact layer (thickness 45 .mu.m) 110 composed of Zn-doped p-type GaAs are grown one by one by a liquid phase epitaxial growth process (hereinafter, referred to as LPE growth process). Finally, a p (positive) electrode 111 and an n (negative) electrode 112 composed of, for example, Au--Ge and Au--Zn are formed and thereafter the wafer is divided into individual semiconductor laser devices.
In the above method of fabricating a semiconductor laser device, the process using the LPE growth process is carried out by a growth slide board 115 made of carbon as shown in FIGS. 9A through 9D. As shown in FIG. 9A, a substrate 102b on which the semiconductor multilayer film has been grown is set at a recess of a base 116, while an LPE-grown clad-layer growth use fused liquid 117 and a contact-layer growth use fused liquid 118 are set at growth fused liquid sumps. The liquid phase epitaxial growth (hereinafter, referred to as LPE growth) is carried out while the temperature is gradually lowered. As shown in FIGS. 9B and 9C, a slider 120 is pulled by a slide bar 119 at a time point when a specified time or temperature is reached, so that the growth fused liquids 117, 118 are switched over. Finally, as shown in FIG. 9D, the slider 120 is further pulled so that the growth fused liquid 118 is removed from the substrate 102b. Thus, the growth is completed.
The above conventional semiconductor light-emitting device has had the following problems:
(1) A semiconductor laser device like the prior art example uses Zn as the p-type impurity for the LPE-grown clad layer and the contact layer. However, Zn has an high vapor pressure and therefore easy to evaporate such that even if it is charged in the growth fused liquid, its concentration in the fused liquid will not be stabilized. PA0 (2) The aforementioned p-type impurity Zn is intensely diffused in the solid phase, being diffused into the lower semiconductor multilayer film during the growth at high temperature, affecting the carrier concentration. This causes deviations from the design structure of the semiconductor laser device and moreover leads to reduction in reproducibility. PA0 (3) The contact layer of the semiconductor laser device such as shown in the prior art example is grown to a large thickness as much as 45 .mu.m, requiring a long time to attain such a growth. However, the growth temperature decreases with time so that the p-type impurity Zn is captured into the growing layer in gradually decreasing amounts. Therefore, the resistance of the contact layer becomes higher as the growth progresses, so that the operating voltage of the semiconductor laser device becomes higher. PA0 (4) The slider is pulled at an end of the growth of the contact layer so that the contact layer growth use fused liquid is removed from the substrate on which the semiconductor multilayer film has been grown, whereby the growth is terminated. This method may cause the bottom portion of the slider to be damaged by an edge growth portion of the contact layer that forms an extremely thin, high grown portion around the substrate. This in turn may cause growth defects to occur in the next and following growths. PA0 (5) Generally in semiconductor laser devices, the active layer for use of laser beam oscillation is advantageously arranged in a generally center of an end surface from which the laser beam is emitted, in terms of improvement in characteristics, relaxation of stress applied to the active layer, improvement in the operating life, and the like. In the semiconductor laser device and its fabricating method such as shown in the prior art example, however, an attempt to arrange the active layer generally in the center would require the contact layer to be grown to a thickness as much as 45 .mu.m, so that the p-type impurity Zn would be diffused into the lower semiconductor multilayer film during the growth. This may cause the semiconductor laser device to be deteriorated in characteristics, as still another problem. PA0 (1) The semiconductor laser device comprises a clad layer composed of p-type AlGaAs doped with Mg instead of the conventional p-type impurity Zn, and a contact layer composed of p-type GaAs doped also with Mg as the p-type impurity. PA0 (2) The active layer for use of laser beam oscillation is arranged in a substantially center of an end surface from which the laser beam is emitted. PA0 (3) The method for fabricating the semiconductor laser device comprises a step of forming a clad layer composed of p-type AlGaAs doped with Mg as the p-type impurity, and a step of forming a contact layer composed of p-type GaAs doped with Mg as the p-type impurity. Also, the method uses an LPE growth process for forming the clad layer and the contact layer, and comprises a step of growing the contact layer from a growth start temperature to room temperature.

Semiconductor laser device having clad and contact layers respectively doped with Mg and method for fabricating the same


A motor-assisted turbocharger is composed of a turbine driven by energy of exhaust gas, a compressor rotated by the turbine and a rotary electric machine for assisting rotation of the compressor. The turbine, the compressor and the rotary electric machine are connected to each other by a common rotating shaft. A polygon nut having magnetic member facing fixed magnetic sensor is connected to an axial end of the rotating shaft. A magnetic field formed between the magnetic member and the magnetic sensor changes according to rotation of the rotating shaft. A rotational speed and a rotational position (or angle) of the compressor are detected based on the changes in the magnetic field. Operation of the turbocharger is electronically controlled based on the detected rotational speed and the rotational position.

1. Field of the Invention
The present invention relates to a rotational speed detector, and more particularly to a device for detecting a rotational speed and a rotational position of a rotating shaft of a supercharger compressor for used in an internal combustion engine.
2. Description of Related Art
A supercharger is used for compressing air to be supplied to an intake manifold of an internal combustion engine to obtain a higher output of the engine. A compressor of the supercharger is driven by various methods. For example, the compressor is rotated by a turbine driven by energy of exhaust gas. The compressor may be directly driven by a rotational torque of a crankshaft of an engine, or by an independent electric motor. The supercharger driven by the exhaust gas turbine (referred to as a turbocharger) may be assisted by an electric motor. This type of supercharger is referred to as a motor-assisted turbocharger.
In the supercharger, it is required to accurately detect a rotational speed and a rotational position of the compressor in order to adequately control operation of the supercharger. For example, in the turbocharger, an opening degree of a valve for introducing exhaust gas into a turbine is controlled based on a rotational speed of a compressor. In the motor-assisted turbocharger, a rotary electric machine is used as a motor for assisting the torque for driving the compressor when the engine is operating under a heavy load at a low speed. On the other hand, when the engine is operating under a light load at a high speed, the rotary electric machine is used as a generator for charging an on-board battery. It is also possible to drive another motor for assisting the engine by the electric power stored in the on-board battery. The rotary electric machine used in the motor-assisted turbocharger is switched to a motor or a generator according to a rotational speed and a rotational position of the compressor.
To detect a rotational speed and a rotational position of a compressor in a motor-assisted turbocharger, JP-A-5-79340 proposes a device in which a permanent magnet is embedded in a compressor blade and magnetic poles are disposed in a stationary member facing the compressor blade. The permanent magnet is embedded in the compressor blade so that its longitudinal direction extends in the traveling direction of the blade and the longitudinal length (a distance between poles of the permanent magnet) coincides with a distance between the magnetic poles disposed in the stationary member. The rotational speed and the rotational position of the compressor blade are detected based on magnetic flux that changes according to rotation of the compressor blade.
In the detecting device disclosed in JP-A-5-79340, however, the following problems are involved. Since the permanent magnet is embedded in the rotating compressor blade, a certain unbalance appears in the compressor blade. Further, a process of forming the compressor blade becomes complex because the permanent magnet has to be embedded in the compressor blade, making the manufacturing cost high.

Rotational speed and position detector for supercharger


A friction clutch having a friction plate and a pressure plate located within the friction clutch housing. The friction clutch has a backing plate that is positioned between the friction plate and the pressure plate with the backing plate being made from a harder material, such as steel, than the pressure plate which is made from a softer material, such as aluminum.

Friction type clutches are well known in the art. Friction type clutches generally comprise two discs. The first disc is more substantial and is usually the engine flywheel; the other disk is usually lighter and commonly referred to as the pressure plate. The flywheel is bolted to a flange on the end of the crankshaft, while the pressure plate slides axially on the output shaft. A spring mechanism is used to press the pressure plate against the flywheel.
In these general friction type clutches, engine torque is transmitted from the engine flywheel to the pressure plate by the friction between the two abutting forces. Because of this large amount of torque, the surface of the discs need to be formulated from a material having a high coefficient of friction, coupled with good wearing properties. The materials that are used to create these products often are too heavy and too expensive.
In other applications, clutch systems are used as part of a transfer case in a four-wheel drive vehicle. The transfer case transmits power (torque) to the front wheels of the vehicle from the rear wheels. The clutch is used to transmit this power from the rear input shaft to the front output shaft. The pressure plate applies the force to the clutch so that it engages and power is transmitted.
Methods and apparatus have been used to try to improve transfer case clutch systems and basic clutch systems in general. Some of these prior systems have tried to extend the life of the clutch disks, but they often proved to be too heavy and/or expensive.

Clutch pressure plate with backing plate


Image information for one screen is read while moving an image taking device so that a sampling position is shifted to make a round and to return the original position in n frames. The sampling position is shifted after stored signal charges of each of the n frames are transmitted to a transmission section and signal charges stored in a photoelectric conversion section are discharged at latest by the end of sampling position shift, thereby discharging outside signal charges stored during sampling position shift.

1. Field of the Invention
This invention relates to reading an image while moving an image taking device such as a CCD (charge coupled device) sensor, thereby obtaining a picture of high resolution.
2. Description of the Related Art
An image reader using an image taking device such as a CCD sensor has been rapidly put into wide use, and recently there is a demand for an image reader having a higher resolving power.
Resolving power of an image reader can be improved in various ways. For example, as disclosed in Japanese Unexamined Patent Publication Nos. 64(1989)-863, 53(1978)-101939 and 1(1989)-221065, by changing relative positions of picture elements of a CCD with time, thereby increasing sampling points, a high resolution picture can be obtained with a CCD having a relatively small number of picture elements. For example, shifting the CCD by a half of the picture element pitch in both the horizontal and vertical directions is equivalent to doubling the picture elements of the CCD in both the horizontal and vertical directions.
When the CCD is shifted in both the horizontal and vertical directions as described above, the image of one screen is formed by four frames which are sampled in different positions.
The resolving power of the image reader can be improved by moving the sampling-position as described above. However since the CCD stores signal charges even during shift, the resolving power cannot simply depend upon the number of picture elements.
Such a deterioration in the resolving power due to shift of the sampling position can be avoided by not using the signal charges stored during the shift, e.g., by intermittently reading an image in synchronization with the shift of the sampling position. However this approach gives rise to a problem that it takes a longer time to read the image since the image reading is repeatedly interrupted.
The deterioration in the resolving power can also be avoided by idly reading one frame image information after the sampling position shift or by discharging or wasting signal charges of one field. However either of the methods also gives rise to a problem that it takes a longer time to read image information for each screen.

Image reading during movement of an imaging device


The present invention provides an underground-environment simulator which simulates underground environment spaces used for radioactive waste disposal or the like, and has a hermetic box, wherein the carbon dioxide gas concentration inside the box can be adjusted to an optional level, and the atmosphere inside the box can be uniformly and stably maintained. In the underground-environment simulator of the present invention, a carbon dioxide gas feeding means feeds carbon dioxide gas into a circulating gas circulation which controls the atmosphere inside the hermetic box, and the concentration of carbon dioxide gas in the circulating gas is measured and adjusted to a predetermined level while oxygen is removed from the circulating gas in an oxyhydrogen reactor. Accordingly, the carbon dioxide gas concentration can be controlled within a low concentration range, and various underground environments can be accurately simulated by varying the carbon dioxide gas concentration to an optional level.

1. Field of the Invention
The present invention relates to an underground-environment simulator which simulates underground environment spaces used for radioactive waste disposal or the like. More particularly, the present invention relates to an underground-environment simulator having a box whose atmosphere is controllable, and being substantially free from stagnation of the gas flow inside the box.
2. Description of the Related Art
Recently, various investigations are being conducted concerning disposal of highly radioactive wastes derived from the nuclear fuel cycle. In such investigations, there is an increasing demand for actualizing, in a simulating manner, an underground environment (with a low oxygen concentration and an optional low carbon dioxide gas concentration) at a depth of a few hundred meters or more where such wastes are disposed, and performing experiments in such an environment.
Such experiments are carried out using a hermetic box, the atmosphere inside which can be isolated from the surroundings. When a radioactive material is treated in the box, the inside of the box is always maintained at a negative pressure in order to prevent external leakage of the radioactive material. For control of the atmosphere inside the box, an inlet pipe and an exhaust pipe are provided on an outer wall of the box, a gas-controlling unit is connected to such inlet pipe and exhaust pipe, and thus an underground-environment simulator is constructed.
Hitherto, in such an experimental facility, a vacuum state is achieved by exhausting the gas inside the hermetic box 51, or most parts of the oxygen and carbon dioxide gas are removed by feeding an inert gas such as nitrogen from an inert gas feeding unit 52 after the inside of the box is purged with nitrogen at ordinary pressure, as shown in FIG. 3. Subsequently, while the inert gas fed into the hermetic box 51 is circulated together with the remaining oxygen and carbon dioxide gas, the remaining oxygen is removed through a deoxygenating unit 53 provided in the circulation path. Further, moisture and the remaining carbon dioxide gas is removed through a water adsorbing unit 54 and a carbon dioxide gas adsorbing unit 55 which are connected in parallel. As a result, an underground environment at an extremely deep place with extremely low oxygen and carbon dioxide gas concentrations is achieved (cf. Japanese Unexamined Patent Publication No. 1-207748).
Actual underground environments, however, differ in carbon dioxide gas concentration according to depth and geological features, though the oxygen concentrations are similarly low substantially without being affected by temperature. When actual underground environments which differ in gas concentration as above should be more closely simulated, the above-described continuous removal of oxygen and carbon dioxide gas by circulation is insufficient. In particular, carbon dioxide gas concentration is a factor influencing experimental results of radioactive wastes greatly even with an only slight variations thereof, and highly accurate experiments require simulation of underground environments with controlled or varied carbon dioxide gas concentration.
Additionally, also in the hermetic box, the atmosphere is needed to be controlled so as to uniformly and stably retain a predetermined gas composition. However, merely adjusting the connecting positions of the gas inlet pipe and the exhaust pipe relative to the outer wall of the hermetic box could rarely achieve uniform distributions of the gases circulating in the box through these pipes. For example, a specific gas can be unevenly distributed at the corner portions of the box.
More particularly, such a hermetic box is provided with openings for gloves needed for experimental operations, a monitoring window, connecters for connecting external measuring equipment, and others, and these portions have sealing regions for preventing external air from entering. Although such sealing regions comprise sealing materials such as natural rubber, neobutylene, teflon, hydrochlorinated rubber and butyl rubber, oxygen in the air can permeate such sealing materials and enter into the inside of the box. In addition, since the inside of the box used for treatment of radioactive materials is set at a negative pressure, external air can leak into the box through the sealing regions when deterioration occurs thereat. As a result of leakage and entering of oxygen or the like by such permeation, gas concentrations readily become uneven in positions close to the internal walls of the box. Further, when drifting or whirling occurs in the gas flow inside the box, the internal atmosphere can rarely be controlled to maintain a predetermined composition during operation, and a long time period is needed for the start-up of operation to achieve a predetermined internal atmosphere.


A method for monitoring insurance, which includes steps of storing a plurality of Tax Records in a database, where each Tax Record corresponds to one or more insurance agreements, and permitting the display of at least one of the plurality of Tax Records. The method assists insurers with multinational customers in keeping track of insurance agreements, and ensuring compliance with legal, regulatory and tax requirements across different states, nations or jurisdictions.

Many insurance companies have customers with bases of operation in more than one U.S. state, and in many cases in more than one national country. Because of the legal, regulatory and tax differences between different states, nations and jurisdictions, most insurance companies underwrite policies from a particular location, to a Policyholder (i.e., First Named Insured) in that same location. For example, an insurance company based in Pennsylvania would only underwrite insurance to Pennsylvania residents or entities. However, in some cases, insurance companies in one state, nation or jurisdiction underwrite insurance providing coverage to risk exposures pertaining to that same Policyholder (or a different Policyholder) located in another state, nation or jurisdiction. Examples may be states, nations or jurisdictions, where there are registered subsidiaries of the Policyholder, or where the Policyholder has property, representative offices, registered directors and officers, etc. In such cases, the insurance companies must ensure to act in accordance with the legal, regulatory and tax requirements for such other state, nation or jurisdiction. Such business practice is also known as Cross Border (CB) or Out Of Territory (OOT) coverage. When policies number in the thousands, and states, nations and jurisdictions in the hundreds, keeping track of all the different legal, regulatory and tax requirements can be cumbersome.
Additionally, some states, nations and jurisdictions place significant restrictions on 'non-admitted' or Out Of Territory (OOT) insurance companies, and in some cases do not permit such companies to insure risks or exposures located in their territories. For example under certain conditions and at the time being, Brazil, China, Japan, the Russian Federation, Switzerland, India, Malaysia, Mexico, Turkey, Thailand and Hong Kong all place significant restrictions on OOT insurance companies, irrespective of the place, where the insurance contract is negotiated. For example, if an US-based insurer is providing insurance coverage to a customer's premises or other exposure which is physically located in Switzerland, then, the US-based insurer is not permitted to do so without obtaining the proper authorization (license) from the Swiss insurance regulator (i.e., the Swiss Federal Office of Private Insurance (FOPI)), irrespective of the fact that this insurance coverage probably is negotiated and underwritten outside of Switzerland, in the US.
Accordingly, there is presently a need for a system and method for monitoring multinational insurance which allows insurance policies to be efficiently issued across different states, nations and jurisdictions, and which ensures compliance with legal, regulatory and tax requirements across different states, nations or jurisdictions.

System and method for monitoring multinational insurance


A support system attaches a hoist to the External Stores Support System of an aircraft by using a boom from which a first leg depends and is attached to a forward fitting. A second leg is attached to the boom via a collar and attaches to an aft fitting while a torque arm is pivotally attached to the collar via a support arm, the torque arm also attaches to a tie-down fitting. The legs are attached to their respective fittings using pins and the torque arm is bolted to the tie-down ring fitting. A hoist slip having a horn is attached to an end of the boom.

1. Field of the Invention
The present invention relates to a hoist support apparatus for mounting various hoists thereto, the apparatus being quickly and removably attachable to an existing external stores support system found on a helicopter.
2. Background of the Prior Art
The use of helicopters for hoisting cargo into or out of the aircraft has been well known for a long time. The helicopter, by being able to fly over areas that may be impossible to reach by land or water vehicles, can reach areas that may be otherwise inaccessible. By being able to hover in place, the helicopter can remain relatively stationary and either hoist cargo, such as relief supplies, from the aircraft, or hoist victims up into the aircraft. The helicopter has proved it is an invaluable tool in many disasters both large and small.
However, the hoist systems known in the art suffer from certain shortcomings. Many hoist systems are mounted within the interior cabin of the aircraft taking up valuable real estate therein, thereby limiting the cargo or passengers that can be ferried as well as creating an obstruction within the aircraft for helicopter personnel. Many hoist systems are relatively permanent in their helicopter installation so that the real estate reduction and obstruction occasioned by the hoist system occurs irrespective of whether or not the helicopter is on a hoist requiring supply or rescue mission.
To lessen the impact of such internally mounted hoist systems, devices have been designed that allow the hoist system to pivot or otherwise fold up in order to reduce the space impact of the hoist system. While freeing up room in the aircraft and lessening the obstruction impact, such devices add substantial weight to the aircraft, limiting the helicopter's ability to transport cargo or passengers.
Other devices are relatively lightweight yet require substantial time and effort of up to thirty days to install the device onto the aircraft, including the need to perform permanent modifications to the original airframe, which modifications need to be performed by specialized personal. As has been recently seen in overwhelming natural disasters including Hurricane Katrina and the Asian Tsunami, the need to modify a large number of helicopters by a limited number of capable personal, dampened the availability of hoist capable helicopters onsite in the unfolding hours and days of the disasters. These delays had a substantial adverse effect on the rescue effort.
As a result, national interests, both civilian and military, have paid greater focus on acquiring larger numbers of hoist capable helicopters, yet such interests are finding the drawbacks associated with current helicopter hoist mount systems to be a daunting challenge.
What is needed is a device that can mount a hoist to a helicopter, which device overcomes the above mentioned shortcoming found in the art. Specifically, the mount system must be able to attach a wide variety of available hoists to the aircraft without the need to make major permanent changes to the airframe of the helicopter. Such a device must be able to be mounted to the helicopter quickly and easily without the need for highly specialized technicians to perform the installation. Such a device must not take away valuable real estate within the aircraft and must not create an undue obstruction burden. Ideally, such a device is relatively lightweight so that the aircraft can carry its typical payload.

Hoist support removably mountable externally onto a helicopter


The present invention relates to cross-linked vacuum skin packaging (VSP) films used as top webs for VSP packages endowed with easy opening features and to VSP packages obtained therefrom. The films of the invention comprise at least one layer of a frangible blend of incompatible polymers. The easy-to-open VSP packages obtained therefrom may advantageously include very simple and cheap supports.

In packaging, there is a need for films that can be used to securely package articles and at the same time allow the easy openability of the package.
A wide variety of products, especially food products like meat, sausages, cheese and the like, are being offered in visually attractive packages made from two thermoplastic webs or of a top flexible thermoplastic web and a bottom support, by using vacuum skin packaging.
In a vacuum skin packaging process, a product is placed on the support, that can be flat or shaped, e.g., tray-shaped, bowl-shaped or cup-shaped (called "bottom" web), and the supported product is then passed to a chamber where a "top" web is first drawn upward against a heated dome and then draped down, upon and around the product, and against the support, the space between the upper film and the support having been evacuated by differential air pressure. The top heated film thus forms a tight skin around the product and seals to the support not covered by the product.
In this kind of packaging process, the whole surface of the top film exceeding the product is sealed to the support all around the product, under vacuum, and the wide area to peel makes the package difficult to open and it may require the use of scissors, knives or other cutting and dangerous devices. To overcome this problem, packages that can be manually opened called "easy-to-open" or "EZO" packages have been introduced into the market. Generally, EZO packages are opened by manually pulling apart the top web from the bottom, normally starting from a point like a corner of the package where the upper web has purposely not been sealed to the support.
The easy-to-open packages of the prior art essentially exploited three opening mechanisms.
In the first one ("peelable easy opening') the package is opened by separating the two webs at the seal interface.
In the second mechanism ("adhesive failure') the opening of the package is achieved through delamination of the seal layer—of the bottom or of the top web—from the underlying remaining layer(s) of the support or of the top respectively. When the delamination reaches the area of the packed products, a second breakage through the sealing layer takes place and a portion of sealing layer is left sealed to the opposite web.
The third system is based on a "cohesive failure" mechanism. In this latter system, easy opening is achieved by internal rupture of a seal layer or of an adjacent layer that, during opening of the package, breaks along a plane parallel to the layer itself.
Easy-to-open VSP packages based on cohesive failure are disclosed, for instance, in EP192131B1, which describes an easy-to-open package with a bottom web seal layer comprising a binary blend of an ionomer and a modified ethylene/vinyl acetate copolymer.
This system is based on the different chemical nature of the two components. The two polymers are only partially compatible and consequently the material fails when a transverse force is applied to this layer thus opening the package.
VSP packages, comprising improved easy opening cohesive failure blends (EZO blends also named frangible blends) in a non-cross-linked bottom web, are disclosed in WO9954398A1 in the name of Cryovac Inc.
This document does not specifically disclose nor exemplifies any embodiment in which the EZO blend is placed in the top web. Furthermore, it never discloses or suggests cross-linking EZO films comprising a layer of EZO frangible blend: in the packages disclosed in WO9954398A1, the bottom web including the EZO frangible blend is never cross-linked.
The EZO VSP packages taught in this document require both top and bottom webs of a certain degree of complexity.
U.S. Pat. No. 5,346,735 describes a multilayer gas barrier composite film, which includes coextruded permeable and impermeable films, useful for VSP packaging.
For blooming the packaged meat, the impermeable film may be peeled off and separated from the permeable film.
The separation of the films of the composite occurs by delamination of layers (adhesive failure at the interface) and not by cohesive failure of incompatible polymers within a layer.
Incorporating the EZO frangible blend in the bottom web, as in the EZO VSP packages based on cohesive failure mechanism currently on the market, requires highly engineered bottom webs, which, in addition to good mechanics for the supporting function, to possible formability, sealing and barrier properties, need also to include the easy opening features.
As a consequence, due to the very high and generally different requirements needed both for top and bottom components, the manufacture of the current EZO VSP packages having the EZO feature in the bottom web does not allow to use simple, cheap, standard supports not tailored for the specific destination of use. In other words, the current EZO VSP solution is technologically quite complex, has little versatility and, consequently, it is rather expensive.
Accordingly, there is still the need for VSP packages that, even if endowed with all the properties mentioned above and, particularly, of an easy opening, would include much simpler and cheaper bottom structures, thus significantly reducing the complexity of bottom support manufacturing and the related costs.

Easy opening film for vacuum skin packaging


A computer implemented method is provided for recommending at least one author of a plurality of authors to a user based on a learned lexicon of the user. First communication content pertaining to a user is obtained. Second communication content pertaining to an author is obtained. A lexicon of the user is learned from the first communication content to identify a set of words known to the user. High frequency words are identified from the second communication content of the author, the high frequency words being one or more words having an occurrence frequency in the second communication content that is higher than a first predetermined threshold occurrence frequency level. The author is suggested to the user upon detecting that the high frequency words are not in the lexicon of the user.

The present invention relates to the field of natural language processing, and more specifically, author recommendation using tokenization from natural language processing to expand a personal lexicon of a user.
In some systems, communication content consists of text, audio, and even transformation of images to text by object recognition, expressed in a computer-readable format. This content is often user-generated and includes both professional and personal written works. Examples of communication content include websites, books, publications, and social media posts. Some communication content, such as social media posts, often contain metadata about the content to help provide not only content, but context. Metadata often includes information about location, engagement, and links shared. Communication content may provide insights regarding content creators, as content parsed from the communication content can be utilized by a number of applications. For example, social media posts may be parsed to help identify appropriate targeted advertising.
Natural language processing is a field concerned with the interactions between computers and human (natural) languages. Tokenization is the process of utilizing natural language processing to break-up a stream of text into words, phrases, symbols, or other meaningful elements called tokens. Tokenization typically occurs at the word level and takes into consideration punctuation, spaces, contractions, hyphens, and emoticons. Tokens generated from content may become input for further processing.

Recommending authors to expand personal lexicon

INTERNATIONAL BUSINESS MACHINES CORPORATION


Yield strength of a cold rolled steel section is increased and controlled by performing a predetermined amount of strain by way of cold working in an in-line roll forming process followed by a controlled amount of strain aging wherein the temperature of the steel section is elevated to a point below 500.degree. C. and held at an elevated temperature for a time up to 30 seconds. The heating typically takes place by induction heaters (16) and the time aging may be provided in an in-line galvanizing bath (17) before cooling the steel in a quench bath (18). The effect is further enhanced by further cold working and the consequent additional strain in forming rolls (19). For a given steel composition the degree of yield enhancement can be controlled by the temperature and tie parameters and also by the degree of initial roll forming in shaping rolls (10).

The process of forming steel strip into desired structural shapes such as rectangular hollow section, circular tube, angles, channels and other open profile sections is well known and has been in use for many years. The feed material is normally so-called "black" steel which has typically been formed into steel strip by a hot rolling process in a manufacturing mill.
In the past one normally recognised method of obtaining increased yield strength of the finished product formed from a subsequent cold rolling process, is to alter the "chemistry" of the steel strip, i.e. by adding various alloying metals into the composition of the steel before hot rolling. Another method is the use of thermomechanical practice during hot rolling. These are expensive processes due to the cost of the metal alloy and the process for obtaining the desired mix of alloy, the technological cost of processing by thermomechanical practices, and also because of the necessity to keep inventory of different types of metal section in order to meet the demand for different performance characteristics at an economical price.
For these reasons, the vast majority of all cold rolled steel sections are formed from common black steel with the size and weight of the section simply being increased where desired to obtain the necessary load-bearing characteristics.
There are however many applications where it is desirable from both engineering and economic points of view to enhance the yield characteristics of the steel from which a structural section is formed in order to give increased performance compared with a similar section rolled from black steel in the conventional manner.

Method of increasing the yield strength of cold formed steel sections


The present invention provides an access method and a system for a Machine-Type Communication (MTC) device, and an MTC device. The method comprises the steps of: an MTC device sending, when performing channel request, a channel request cause value and a random reference value to a Base Station Subsystem (BSS) (100), and the BSS sending the received channel request cause value and random reference value back to the MTC device when completing channel allocation (101). The present invention distinguishes the MTC services from other non-MTC services through the channel request cause value, that is, when the cause values are different, the collision will not occur even if the random reference values are the same, thus reducing the probability of the random reference value collision, implementing the effective management for access operations of large numbers of MTC devices, and avoiding the influence of random reference value collision on the normal implementation of original services.

With the development of communication technologies, the MTC communication technology has received much attention. The MTC communication technology, which combines data collection, remote monitoring, telecommunication and information technology, can make the service flow automated, integrate the real-time state of Information Technology (IT) system and non-IT equipment in the company, and create value-added services. In the MTC communication system, terminal equipment is referred to as MTC device.
In the present MTC communication technology, as the wireless network side does not provide specialized optimization processing measures for the access operation of an MTC device, the load condition of wireless network resources cannot be taken into consideration during the access of the MTC device. Therefore, the MTC device still tries to access even when the wireless network has no available network resources, which makes the MTC device unable to access the wireless network. Or, even if the MTC device is able to access the wireless network successfully, but in the end, the performance of the wireless network is affected due to excessive number of MTC devices in the wireless network, thereby affecting the normal operations of other MTC devices.
With the unceasing maturation of the MTC communication technology, large numbers of MTC devices will be added to the MTC communication system. If the access operations of the MTC devices are not optimized, there is no doubt that the performance of the wireless network will be affected.
In the prior art, when a mobile terminal accesses the network, the mobile terminal will send a Channel Request message to a Base Station Subsystem (BSS), and at the same time carries a Random Reference cell in the Channel Request message. After channel allocation is finished by the network, the random reference will be carried in an Immediate Assignnment message which is sent to the mobile terminal, so that the mobile terminal is able to identify which Immediate Assignment message is sent to the mobile terminal itself. Here, the base station subsystem is the bridge of communication between the mobile terminal and a mobile switching center.
At present, the longest Random Reference specified in the protocol is only 5 bits, so there are only 32 random reference values. In such a way, when large numbers of MTC devices are trying to access the wireless network, there is a case that multiple terminals may use the same random reference value. Therefore, this will cause random reference value collision, and two or more terminals will access the same channel at the same time, so that the service cannot be normally implemented.

Access method and system for MTC device, and MTC device