Provided are a method for preparing a transparent conductive layer and a transparent conductive layer prepared by the method. The method for preparing a transparent conductive layer includes: 1) forming a cellulose derivative film by coating a transparent substrate with a cellulose derivative coating liquid; 2) hydrolyzing the cellulose derivatives by treating the cellulose derivative film using an alkaline agent; 3) forming a metal film by coating the hydrolyzed cellulose derivative film with an organic metal ink and reducing metals on the cellulose derivative; and 4) forming a conductive metal layer by heat-treating the cellulose derivative film with the metal film formed, and a transparent conductive layer prepared by the method. According to the present invention, a process can be simplified, and also a transparent conductive layer having excellent conductivity, transmittance, bending resistance, and low haze can be prepared.

Generally, a transparent conductive layer is used as an essential component of electric and electronic devices such as a power source in display devices, an electromagnetic wave shielding film in home appliances, a transparent electrode in various display fields such as a liquid crystal display (LCD), an organic light emitting diodes (OLED), a field emission display (FED), a plasma display panel (PDP), a flexible display, an electronic paper, or the like.
Currently, as a material of the transparent conductive layer, a conductive inorganic oxide material such as indium-tin oxide (ITO), antimony-tin oxide (ATO), antimony-zinc oxide (AZO), or the like, is mainly used.
The transparent conductive layer having relatively high conductivity and transmittance may be prepared using the material by a sputtering method, an ion beam method, a vacuum deposition method, or the like, that are generally used. However, in this method, cost for equipment investment is high, and it is difficult to mass-produce the transparent conductive layer and prepare a large size transparent conductive layer. Particularly, this method has a limitation in a transparent substrate requiring a low temperature process, such as a plastic film. At the time of deposition by the sputtering method, composition of the transparent conductive layer may be changed according to the conditions such as oxygen partial pressure, a temperature, and the like, and the transmittance and resistance of the thin film may be rapidly changed. In addition, even after the process is completed, a crack may be generated in the thin film, which increases the resistance. Therefore, a method for preparing a transparent conductive layer performed by coating a film using a wet coating method such as a spin coating method, a spray coating method, a dip coating method, a printing method, or the like, that are appropriate for low cost and a large size and then firing the coating film, or the like, has been suggested. For example, a transparent conductive layer using a metal fine particle and a binder is disclosed in Korean Patent Laid-Open Publication No. 1999-011487, a composition for a transparent conductive layer in which a hollow carbon nano fiber is added to tin oxide is disclosed in Korean Patent Laid-Open Publication No. 1999-064113, and a coating solution for a transparent conductive light selectively absorbing film in which neodymium oxide is added to tin oxide or indium oxide was disclosed in Korean Patent Laid-Open Publication No. 2000-009405. In addition, a method for manufacturing a solution for a transparent conductive layer containing a metal particle such as gold, silver, or the like, is disclosed in Japanese Patent Laid-open Publication No. 2003-213441.
A surface resistance of the transparent conductive layer prepared by the above-mentioned methods is high, that is, about 103 to 104Ω/□, time-dependent changes, an increase in the surface resistance according to the change in surroundings and time, or the like, are generated therein, such that initial conductivity may not be maintained. Therefore, this transparent conductive layer has a limitation in being used as the transparent conductive layer.

Transparent conductive film-preparing method and transparent film prepared therefrom


A motor mount for a motor having an elongate drive shaft. The motor mount includes a base having a generally planar surface. At least one elongate rail is disposed at the surface of the base. A motor carriage plate has a generally planar bottom surface disposed approximate to and generally parallel to the surface of the base. The motor carriage plate has at least one rail engaging surface disposed at an angle to the bottom surface. The motor mount includes a motor carriage fastener for fastening the motor to the motor carriage plate. A fastener is provided for attaching the motor carriage plate to the base plate such that the rail engaging surface engages the elongate rail.

The present invention pertains generally to the field of motor mounts and, in particular, to motor mounts for precision alignment of motors.
Motors, and in particular, electric motors, are widely used in industrial applications to drive fans, conveyer belts and other devices. Power is generally transferred from the electric motor by belts and/or couplings. In a simplified application, a pulley is connected to the motor drive shaft, a belt fitted to the pulley transfers energy from the drive shaft as the pulley rotates. The belt can be fitted to a second pulley which is, for example, connected to a fan.
Ideally, the pulley fitted to the drive shaft and the pulley fitted to the fan are precisely aligned such that the belt is centered within the respective grooves of the pulleys without being biased toward one or the other side of the grooves. If the belt is biased into the sides of the pulleys due to improper alignment of the pulleys, chafing of the belt can occur. If excessive chafing occurs, the life of the belt can be reduced as well as the efficiency of the power transfer between the two pulleys.
In industrial applications, each time a belt fails, a manufacturing facility may experience a costly shut down of an assembly line if, for example, the power to a conveyer belt is cut. If the belt is then replaced and the pulleys remain improperly aligned, accelerated failure of the belts can be anticipated. When using prior motor mounts, precise alignment of the pulleys after belt replacement would require the use of precision measuring devices used by skilled technicians who may not be readily available to realign the motor. Thus, in order to restart the assembly line, the belt may be replaced without proper realignment. Consequently, accelerated belt failures and assembly line shut downs will continue.


A hub assembly adapted for mounting on a bicycle wheel. The hub assembly includes a hub shell with a first flange and a driver side flange. The assembly is received around a hub axle. The hub axle is received through the hub shell and attached to a bicycle frame. One end of the hub axle is disposed next to the first flange. The end of the hub axle is supported on a first hub axle bearing. Also, the hub assembly includes a cassette body with a cassette body bearing. An opposite end of the hub axle is supported on a second hub axle bearing next to the cassette body bearing. A driver gear, received in a threaded cavity in one side of the driver side flange, is used for driving the hub assembly and the cassette body on the hub axle.

(a) Field of the Invention
This invention relates to a bicycle hub assembly for holding a plurality of chain gear sprockets, commonly called a "cassette", attached to a ratcheting cassette body, and more particularly, but not by way of limitation, to a hub assembly with a cassette body that is supported entirely by a hub shell itself. The hub assembly, used for supporting the cassette body, is designed to eliminate an unsupported span of a rear hub axle common on modern hubs. The benefits of this hub assembly design are: increased lateral rigidity of the rear hub axle, improved bearing durability, improved stiffness to weight ratio of the hub assembly, greater efficiency of torque transfer when applying pedal load to the hub assembly during the operation of a bicycle, and significant improvement to the lateral rigidity of the complete wheel.
(b) Discussion of the Prior Art
Modern day bicycle rear wheel hub assemblies include a cassette body mounted on an unsupported portion of an extended rear hub axle. The cassette body provides for "free wheeling" when coasting on the bicycle, and driving the bicycle when not coasting. The body makes for easy gear sprocket changes and customized gear ratios. But, because the rear hub axle is unsupported when extending outwardly from one side of the rear hub shell, load and alignment problems occur. For example, the extended hub axle span allows the hub axle to flex significantly under lateral and torsion loads. This flexing of the hub axle causes bearing misalignment, which in turn increases loaded drag and leads to premature bearing failure. Also, the flexing of the hub axle significantly reduces the lateral rigidity of the entire rear wheel.
Others have tried to reduce the above mentioned rear hub axle and bearing problems by the use of a stiffer hub axle, which in turn creates additional problems. A stiffer hub axle can be made of steel, rather than lightweight aluminum, with a thick wall to create a significant increase in stiffness. But this approach adds unnecessary weight to the hub assembly.
Another solution by others has been to use a large diameter aluminum hub axle, which can be made reasonably light and stiff. However, this feature requires the use of thin section bearings, which tend to wear out quickly or become damaged, which adds significant drag to the hub assembly.
Still another approach by others has been to use a separate bolt-on cassette body attached to one end of the rear hub assembly. In this example, the cassette body is excessively heavy with a ratchet driver housed inside the body. Because of the diameter constraints of the cassette cogs, the internal diameter of the cassette body is relatively small. Therefore, the ratchet driver inside the cassette body is reduced in size, severely limiting the strength and performance of the hub assembly.
The subject hub assembly, as described herein, provides clear-cut objects, advantages and unique structural features heretofore not incorporated into a rear wheel cassette style hub assembly to eliminate the above mentioned problems related to an unsupported rear hub axle span.

Bicycle hub assembly with cassette housing


A vertical support grid system, such as is used in the construction industry, to particularly provide elevated support for concrete forms and the like, includes vertically extending legs, cross-bracing diagonally spanning the distance between the legs, and tie-bars horizontally spanning the distance between the legs. A bracketing mechanism is provided which allows the quick and easy securement of the cross-braces and tie-bars to the legs at any desired location on the legs.

This invention relates to vertical support systems for use in construction, and in particular to provide elevated support for concrete forms, scaffolding, and the like, and specifically pertains to a bracketing mechanism which allows for quick and easy attachment of cross-bracing and tie-bars to legs of the support system.
Vertical support systems, such as scaffolding, have long been used to provide access to various levels of an ongoing construction project. However, present scaffolding systems are generally fixed in the manner in which they can be set up. There is little or no room for variation in the set up of the support or scaffolding system.


A method and device or electrically charging electric vehicles, wherein a cooling unit makes available a cooling medium, wherein the cooling unit is designed to cool, with the cooling medium, at least two electric charging devices and at least two power electronics apparatuses which are designed to electrically charge electric vehicles.

U.S. Pat. No. 9,061,597 B2, which is incorporated by reference herein, discloses a high-speed charging device and high-speed charging system for electric vehicles as well as a method for cooling the interior of the housing of a high-speed charging stand. In this case, the power supply and the control device are accommodated as a control unit in the housing.
U.S. Pat. No. 6,362,594 B2, which is incorporated by reference herein, discloses a contectless induction charging device with a stand and a power source device which is arranged on the stand and has a housing.
A blower is used for cooling in each housing.

Method and device for electrically charging electric vehicles


Floor and wall covering materials are provided with a barrier layer to inhibit the migration or dispersion of organic stainants from the surface of the underlying floor or wall into the decorative portions of the covering materials. The barrier layer comprises a plastisol and sodium silicate which is coated onto or incorporated into the floor or wall covering in the wet state as a mixture of plastisol and water glass, followed by heating to drive off water and gel or fuse the plastisol. The barrier layer is particularly compatible with sheet vinyl floor and wall covering materials. It can be coated onto the underside of the covering material or incorporated as a layer between the underside and the decorative portion of such material.

1. Field of the Invention
The present invention has to do with a barrier layer which inhibits the migration of underlying organic stain into the decorative portion of floor covering and wall covering materials. More particularly, the invention relates to a barrier layer comprised of a plastisol and sodium silicate which is incorporated into a floor or wall covering to inhibit the migration of organic materials from the surface underlying the floor or wall covering into the decorative portion thereof.
2. Description of Related Art
Floor covering and wall covering materials frequently are applied over surfaces which have been coated or marked with organic substances such as sealants, wood stains, ink from marking pens, asphalt, oil based paints and the like. These organic substances can migrate or diffuse into the floor or wall covering and cause staining of the decorative portion thereof, which destroys the decorative appearance.
Organic substances can cause staining of a variety of floor and wall coverings such as carpeting, sheet vinyl flooring, and cloth or vinyl wall coverings. Sheet vinyl flooring and wall covering products are particularly vulnerable because they contain plasticizers which are compatible with organic substances. The stains thereby diffuse into the floor or wall covering by means of the plasticizer as a vehicle. The higher the plasticizer content, normally, the faster the stain diffuses. According to the preferred embodiment of the present invention, a barrier which inhibits such migration is incorporated in the sheet material as a layer which may be adhered as the back or underside of the sheet material, or incorporated between the back and the decorative portion of the sheet material.
Sodium silicates, called water glass when they are dissolved in water, have been employed in coatings and adhesives. U.S. Pat. No. 1,365,715, for example, discloses the use of sodium silicate as a replacement for a part of the glue used in sizing compositions. The sizing composition described in the patent employs sodium silicate, an organic adhesive (e.g., glue) and a filler such as clay, casein, or starch in an aqueous solution. The composition is described as particularly adapted for use in sizing wood, paper and similar pulp boards and other articles consisting largely of cellulose or other fibrous or absorbent materials because the sodium silicate causes swelling of the fibers and allows them to be penetrated by the filler, thereby preventing the migration of moisture and organic liquids (e.g., paint) into the cellulosic material.
The use of sodium silicate in aqueous solutions to make water resistant compositions is also disclosed in U.S. Pat. No. 1,949,914. Modified aqueous sodium silicate solutions are described in the patent as containing complex amine compounds which facilitate the production of water resistant films.
In U.S. Pat. No. 1,466,241, a floor covering material is disclosed which consists of a mat covered with a mixture of powdered soya bean or the like albuminous substances, ammonia water, fibers as binding material, and pigment. The patent includes an example wherein sodium silicate is employed to solidify the albuminous substances which have been acted upon and dissolved by the ammonia. A coating is thereby obtained which is described as water proof and almost fireproof.
A method is disclosed in U.S. Pat. No. 2,485,287 for co-precipitating plastic materials and compounding ingredients in aqueous media. The method illustrates the difficulty encountered when one attempts to combine such materials. It requires the association of a coagulable aqueous dispersion of an organic plastic material, such as a natural or synthetic rubber or resin latex, with an aqueous solution of a water soluble reagent which is one component from which the compounding ingredient may be produced by chemical reaction, and with an aqueous solution of a second water soluble reagent reactive with the first reagent to form the compounding ingredient in a manner such that the various reactants remain in substantially distinct layers or moving streams while permitting diffusional intermingling of the separate reactants. A reaction of the water soluble chemical reagents is thereby effected to form the insoluble compounding ingredient in particulate form with simultaneous coagulation of the aqueous dispersion. An aqueous slurry is formed comprising the insoluble compounding ingredient enclosed or enmeshed in the plastic material. The plastic material is said to surround and enclose extremely small particles of insoluble compounding ingredient. An embodiment exemplified in the patent is a method of making a latex having water glass incorporated therein.
U.S. Pat. No. 4,510,201 describes polyvinyl chloride resin compositions combined with a cellular filler which reduces the density of the resin. A cellular filler is incorporated by dry blending polyvinyl chloride resin, a plasticizer, a stabilizer and the cellular filler, in a manner which does not destroy the cellular filler, to make a free flowing powder. Several inorganic cellular fillers are described as suitable, including sodium silicate. The patent also describes polyvinyl chloride sheet products containing cellular fillers which can be used in floor coverings to make them light, superior in flexibility and bending strength, dimensional stability, water resistance and improved adhesiveness.
None of the foregoing references resolve the need for a barrier layer which can be incorporated into a floor or wall covering material to inhibit the migration of organic stainants.

Barrier layer for floor and wall coverings


A catheter system is provided for creating a fistula between blood vessels, using a first catheter with a piercing tool adjacent its distal end, and a second catheter with a receptor adjacent its distal end. The receptor includes an opening and a channel providing a guide surface for receiving the piercing tool. The receptor and piercing tool include one or more magnets to draw the piercing tool into the channel of the receptor. The piercing tool and the receptor are provided with a complementary configuration, such as a mating conical shapes. A third catheter may be provided with a double balloon for use in sealing off the fistula site. The piercing tool may be provided on a metal guidewire that includes a lumen with a distal opening. The piercing tool may include a base and a needle coupled to the base at a nominal angle of at least about 20-degrees. The piercing tool may be selectively moved between an extended position wherein the needle is positioned outside the guidewire at the nominal angle and a retracted position wherein the needle is positioned substantially within the guidewire.

This invention relates generally to a catheter system for connecting adjacent blood vessels, e.g., an artery and an adjacent vein to adapt the vein for arterial blood flow. More particularly the invention concerns a system of two catheters with mating, magnetic tips for creating openings in the artery wall and vein wall to form a fistula connecting the blood vessels.
A catheter apparatus and method for arterializing a section of a vein to bypass a clogged artery are shown in U.S. Pat. No. 6,464,665, which is hereby incorporated by reference. The method is used to bypass a stenosis in the artery that obstructs blood flow in a portion of the artery. If the obstructed portion of the artery can be bypassed, blood flow will be restored downstream from the stenosis. A vein running alongside the artery in the obstructed portion of the artery can be used for the bypass.
The catheter apparatus includes one catheter for inserting into the artery and another catheter for inserting into the adjacent vein. The physician maneuvers the tips of both catheters to coincident positions within each blood vessel adjacent one end of the obstructed portion of the artery. The physician then creates an opening from the inside of one blood vessel through the vessel wall and then through the wall of the other blood vessel. A difficulty here is in co-locating the openings in the two blood vessels and holding the vessel walls in place to ensure that a channel will be created between the vessels so that blood will flow from one vessel to the other.

Catheter system for connecting adjacent blood vessels


A device and method for producing single crystals by the Czohralski method can control the temperature distribution and thermal history of single crystals to improve the production efficiency and quality of single crystals. The device includes a cylinder coaxially surrounding a single crystal pulling rod, having an upper end airtightly connected to the ceiling of a pulling chamber and a lower end close to the surface of a melt in a crucible. A heat insulating element is attached to the lower end of the cylinder, and is surrounded by a surface of the crystal, the inside wall of the crucible and the surface of the melt. The heat insulating element is sized to occupy 30-95% by volume of the space above the melt, and the space has a height corresponding to the radius of the crystal. The heat insulator has a sufficient heat insulating effect, so that even if the diameter of single crystals is increased, the pulling speed of the crystals does not need to be lowered, the uniformity of temperature of the entire crystal-melt interface is improved, and the ratio of single crystallization is not reduced.

1. Technical Field
The present invention relates to a device and method for producing a single crystal, in particular, a device for producing a single crystal by pulling it by the Czochralski method in which the temperature distribution and thermal history of a pulling single crystal are controlled to improve the production efficiency of single crystals and the qualities thereof, and a method for producing a single crystal by using the device.
2 . Background Art
In recent years, high- integration and high- precision of semiconductor devices are more and more advanced, and wafers of semiconductor crystals are becoming larger in diameter and higher in quality. Such semiconductor crystals are mainly produced by the Czochralski method (the pulling method), in which various efforts to produce semiconductor crystals having further large diameter and high quality are made.
For example, explaining such a case that a silicon single crystal rod is produced by the Czochralski method as shown in FIG. 4, a pulling chamber (a metal chamber) 1 is provided with a quartz crucible 3 in the middle, the quartz crucible 3 being supported by a graphite susceptor 4 which is supported at the center of the bottom by a supporting shaft 4 which is rotatable and up- and- down movable. The quartz crucible is filled with a raw material, polycrystalline silicon, which is heated and melted by a graphite heater 6 surrounded with a heat insulating cylinder 5 to give melt 7. The pulling chamber 1 has an opening part 8 in the middle of the ceiling thereof, to which a sub- chamber 9 is connected. A pulling shaft 11 which is rotatable and up-and- down movable and holds a seed 10 at the end is moved down through the sub- chamber 9, thereby the seed 10 is dipped into the melt 7, and subsequently the seed 10 is pulled with rotating the pulling shaft 11 and the quartz crucible 3, thereby a single crystal rod 12 can be grown following the end part of the seed 10. The problems arising when single crystal rods are produced by such a conventional Czochralski method are as follows: First, in pulling a crystal, a protective gas such as, for example, argon gas, is introduced from the upper part of the sub- chamber 9 and discharged from a discharge outlet 15. The gas to be introduced is extremely highly pure, but in the pulling chamber a reaction between the quartz crucible 3 and the silicon melt 7 takes place so that vapor of SiO occurs from the surface of the melt 7, the vapor of SiO being present in the upper part of the inside space of the pulling chamber 7. Most of the vapor of SiO flows downward and is discharged from the discharge outlet 15, but a part thereof is deposited as aggregate of fine powders in a form of layers or masses on such places as those having relatively low temperatures such as an inside wall 16 of the upper part of the quartz crucible 3 or an inside wall 17 of the upper part of the pulling chamber 7, when any turbulent flows 13, 14 are present in the upper part of the inside space of the chamber 7 or around the single crystal rod 12 and the surface of the melt 7. The deposited SiO falls down on the surface of the melt in pulling a single crystal and attaches to the interface of growing the crystal, which results in dislocation of the pulling single crystal rod.
Furthermore, in the pulling chamber, a reaction between carbon materials such as the graphite susceptor 2, the graphite heater 6, the heat insulating cylinder 5 (for example, made of graphite felt) and the like and the above- mentioned SiO or the quartz crucible takes place so that a CO gas occurs. When the turbulent flows 13, 14 are present in the upper part of the inside space of the pulling chamber 7 and around the single crystal rod 12 and the surface of the melt 7, the CO gas flows downward and comes into contact with the surface of the melt, which results in the increase of the concentration of carbon in a pulling single crystal silicon rod and the deterioration of the characteristics of integrated circuit devices on the wafers produced from the single crystal rod.
The pulling speed of the single crystal rod 12 is dependent on a temperature gradient of the single crystal rod on the crystal- melt interface, the temperature gradient being greatly affected by the radiant heat from the graphite susceptor 2, the quartz crucible 3, the surface of the melt and the like to the crystal. In order to improve the productivity of single crystal rods, the pulling speed of the single crystal rod should be as fast as possible. However, if the diameter of a single crystal to be pulled is larger, the latent heat for crystallization as well as the above- mentioned radiant heat are increased so that the pulling speed of the crystal is decreased and the productivity thereof is also remarkably lowered. If a crystal to be pulled is larger in diameter, it becomes difficult to uniform the temperature of the entire crystal- melt interface so that the ratio of single crystallization is decreased and the yield of single crystals is remarkably reduced.
Regarding qualities of crystals, for example, in a case where integrated circuit devices are formed on a wafer of a silicon single crystal, oxidation induced stacking faults (hereinafter, referred to as OSF's), swirl defects and other microdefects are easily formed in a thermal oxidation process, which lead to the deterioration of the characteristics of integrated circuit devices. Using any conventional devices by the Czochralski method, however, it is difficult to completely suppress the generation of these defects, this tendency being more remarkable, in particular, with the diameter of crystals to be pulled becoming larger.
Moreover, the requirements for the qualities of semiconductor crystals become severer with high- integration and high- precision of semiconductor devices being advanced in recent years, so that further high purity, lower level of defect generation and uniformity of single crystals are required. In particularly recent years, it has been proved that not only the higher purity of raw materials and higher cleanness of members of a device used for the production of a single crystal and higher precision of the device but also the thermal history of a growing single crystal has a great influence on the generation of crystal defects and the like. For silicon crystals, for example, it has been confirmed that the levels of OSF's, oxide precipitates, BMD's (bulk micro-defects), FPD's (flow pattern defects), LSTD's (laser scattering tomography defects) and COP's (crystal originated particles) as well as various characteristics such as a dielectric breakdown voltage and the like are affected by the thermal history. For compound semiconductors such as GaP, GaAs, InP and the like, it has been confirmed that the dislocation density and the level of defects which function as a donor or an accepter are greatly influenced by the thermal history. Accordingly, some devices having various structures of the inside of the pulling chamber have been proposed in order to adjust the thermal history of a growing crystal to control the levels of any defects therein, but it is not possible to highly precisely control the thermal history by using such devices.
The following proposals have been made in order to solve the above- mentioned problems:
i) Japanese Patent Publication (KOKOKU) 57-40119
It describes a device for pulling a single crystal in which a crucible 3 and melt 7 therein are partly covered, as shown in FIG. 5, wherein it is provided with a member comprising a flat and circular rim 30, which is above a crucible 3 and projects from the edge of the crucible 3, and a connecting part 31, which is attached to the inside edge of the rim 30 and is in a form of a cylinder or a tapering cone, the inside height of the connecting part 31 being 0.1 to 1.2 times as long as the depth of the crucible 3.
ii) Japanese Patent Laid- Open (KOKAI) 64-65086
It describes a device for producing a single crystal rod, as shown in FIG. 6, wherein it is provided with a cylinder 19 coaxially surrounding a pulling single crystal rod 12, one end of the cylinder 19 being airtightly connected to the edge of the outlet in the middle of the ceiling of a pulling chamber and the other end thereof facing the surface of melt 7 in a quartz crucible 3 and being provided with a collar 20 which is formed by turning up outside and spreading.
These devices have such effects as the increase of the pulling speed, the suppression of SiO precipitates falling into silicon melt, the suppression of generation of OSF's, etc. to some extent. However, they are unsatisfactory under further increase in a desired diameter (in case of silicon single crystals, that are 8 inches or more) and further heightening of the desired qualities of single crystals in recent years.
That is, regarding the device under i), any measures against new requirements for qualities which become problems in recent years, such as a level of OSF's and a dielectric breakdown voltage are not taken, and in the device under i) the covering member is in fact made of relatively thin metal plate, which has a low effect of insulating a pulling single crystal from the radiant heat, so that the device under i) is not suitable for pulling single crystals having a large diameter such as 8 inches or more. Furthermore, since the connecting part 31 which surrounds a single crystal and is in a form of a tapering cone has a low inside height, the crystal, after it is not surrounded with the connecting part 31 in a pulling process, emits radiant heat directly to the metal chamber cooled by water so that it is not capable of controlling the temperature distribution and thermal history of the crystal, and the upper part of the inside space of the pulling chamber is broad so that turbulent flows 14 occur which bring about various harmful influences.
The device under ii) has the cylinder 19 coaxially surrounding a pulling single crystal rod, one end of the cylinder 19 being airtightly connected to the edge of the outlet in the middle of the ceiling of a pulling chamber and the other end thereof facing the surface of melt 7 in a quartz crucible and being provided with a collar 20 which is formed by turning up outside and spreading, so that the straightening effect of a protective gas and the effect of keeping the temperature of a crystal or cooling a crystal are improved in comparison with the device under i), but, since the collar 20 is relatively small and made of thin material, the device under ii) has also only insufficient effects of insulating the crystal from the radiant heat in pulling a single crystal having a large diameter in recent years. In the device under ii), it is possible of adjusting the thermal history of the pulling crystal to some extent by adjusting a spread angle .alpha. of the collar 20, but the range capable of adjusting the thermal history is narrow, and such highly precise and extremely minute control of the thermal history as satisfies all of various qualities of crystals which are required in recent years is not possible.
As mentioned above, since the conventional devices have only an insufficient effect of insulating a crystal from the radiant heat, the range capable of adjusting the thermal history and temperature distribution of crystals is very narrow, so that the change of design of the device for producing a single crystal including the change of the inside structure of the chamber is required every time the diameter of a crystal to be pulled is changed, this meaning a disadvantage of doing all over again.

Device and method for producing single crystal


A transporting apparatus is provided with a moving platform capable of moving vertically, an article loading platform that can be moved horizontally with respect to the moving platform, a contactless sensor provided on the moving platform, a detected member that is provided on the article loading platform, whose position can be altered between an position detected and a position not detected by the contactless sensor, and an operating member operatively linked to the detected member. The operating member can come into contact with an article loaded on the article loading platform, and changes the position of the detected member between the detected position and the non-detected position. Due to this configuration, it is possible to provide an article position sensor between the article loading platform and the moving platform without using wires, which are deteriorated due to the relative movement between the article loading platform and the moving platform.

The present invention relates to transporting apparatuses used in automated warehouses, and more specifically to transporting apparatuses in which a loading platform for transporting articles is provided that is capable of horizontally advancing and retreating to a moving platform that is raised and lowered.
Such a transporting apparatus is disclosed for example in JP 2000-219498A (paragraphs [0017] and [0018], FIGS. 1 and 2), and is an apparatus for transporting articles set on an article loading platform. This apparatus has a vehicle that moves horizontally near the ground, a support column fixed to the vehicle and extending vertically, a raising and lowering stand that moves vertically along this support column, and an article loading platform on which articles are loaded and which can move between a home position and an extended position with respect to the raising and lowering stand. In the position opposite a desired article storage portion, by moving the article loading platform from the raising and lowering stand to the extended position, the article loading platform is inserted under the article, and then by raising up the article loading platform the article is loaded onto the article loading platform and removed from the article accommodating portion. Then, by withdrawing the article loading platform after lowering it with respect to the article through the lowering operation of the raising and lowering stand, the article is stored within the article storage portion.
With this type of transporting apparatus, if there is a change in the position or orientation of an article placed on the article loading platform due to inertia during transfer, for example, then when storing the article in the article storage portion, the article is interfered with by partition frames of the article storage portion. To prevent this from occurring, measures such as stopping operation were necessary.
Thus, conventionally there were devices in which an article loading state detection sensor was provided on the article loading platform, which detected the occurrence of a change in the article loading state by detecting the absence of an article in a detected position of the article loading platform.

Transporting apparatus with position detection sensor


A screw implant for a jawbone has a conical threaded implant body with an implant neck and a conical implant post to accept a replacement tooth or a substructure. The thread of the implant body is a compression thread with concave thread turns.. The implant neck preferably defines a bending zone wherein the ratio of the diameter D.sub.B to the length L.sub.B of the bending zone is in the range of 1:1.5 to 1:3. The bending angle is up to 30 degrees and the number of bendings of the bending zone is 3 to 4, when the implant post is bent back and forth. The implant neck has broadening transition sections.

1. Field of the Invention
The invention relates to a screw implant for a jawbone comprising a threaded conical body which can be screwed into the jawbone, on which is formed an implant neck and a conical implant post to accept a replacement tooth or a substructure.
2. Description of Related Technology
There are many forms of known tooth implants. Only a few of these have found practical application. For example, needle implants and blade or plate and screw implants have been used. Even though screw implants have been found to be especially useful, they have not fulfilled expectations. Proposed forms of such implants have been found to be deficient, especially because of insufficient anchoring, damage to the bone, or because of complicated insertion methods.
German Offenlegungschrift 22 55 916 (May 16, 1974) describes a screw implant which has a helical thread as well as a substantially constant outside diameter. Good initial anchoring is taught to be achievable and the anchoring effect is intended to improve as time progresses. However, it has been found that, since the diameter of the shaft is relatively large, the thread of the shaft cuts into the bone bed during implantation such that destruction of bone tissue cannot be avoided. Voids formed in the threads have an adverse influence on the lifetime of the implant, and also form infection sites. Furthermore, the rigid screw-in implant cannot be bent, as for straightening, after implantation. As a rule, it is only possible to shorten such an implant by grinding of the column or post carried by the implant neck. This is especially unpleasant for the patient, since the grinding has to be done after the insertion of the implant.
Another embodiment of a screw implant as described in Grafelmann, et al. U.S. Pat. No. 4,406,623 (Sep. 27, 1983) has a conical screw shaft with a helical thread. The purpose of this structure is to impart to the implant enhanced strength in the implanted state. It is clear from this patent that, in screw implants, the form of the thread is of special importance, and very precise data are given. V-shaped sections are cut out from the threads of the helical thread winding at angular distances which are smaller than 3600 but not equal to 1800. These cuts are radially directed and, starting from the periphery of the helix, the tips are in the region of the shaft surface. Furthermore, sharpened parts which extend in the direction of insertion are formed. Thus, a very sharply cutting thread is provided and such an implant cuts into the bone relatively deeply. However, this results in bone tissue destruction and development of void spaces. Moreover, straightening of the implant is not possible and here, too, grinding processes must be employed for adaptation.
German Offenlegungschrift 26 00 639 (Jul. 15, 1976) describes an insert for a tooth bed wherein the insert has a nonbendable strengthening extension and a thread, with the threads being cut deeply in such a way that, upon insertion, voids are formed between the insert and the tissues which may lead to inflammation.
A screw-type jaw implant made from ceramic materials is described in Muench U.S. Pat. No. 4,468,200 (Aug. 28, 1984). At a lower end, which is intended for anchoring in the jawbone, a conical screw having a rounded end is provided, and at its upper end is a hollow groove for attachment of the epithelial sleeve and which has an opening to accept a tooth support. This is designed for insertion immediately after a tooth is extracted. There is an annular thickened portion between the upper and lower ends, which is designed as a conical screw and there are at least two annular notches, whereby the diameter of the annular thickened region is smaller than the diameter of the thread peaks at the uppermost thread of the lower part of the jaw implant. In order to achieve an especially secure anchoring, the lower part of the jaw implant is provided with saw tooth-like threads but a disadvantage of these is that the jaw tissue is damaged when the implant is inserted. The thread design does not permit elimination of voids. Moreover, the securing section for holding the replacement tooth cannot be adjusted.
Niznick U.S. Pat. Nos. 4,645,453 (Feb. 24, 1987) and 4,758,161 (Jul. 19, 1988) disclose a dental implant consisting of two parts comprising an anchor and a special bendable adapter which is inserted into the anchor after the anchor is fixed in the jawbone. The bendable adapter may be made of titanium, a titanium alloy, stainless steel or, in U.S. Pat. No. 4,758,167, a thermoplastic material and is bent to a degree determined by prior study and survey. As a result, the location of the adaptor to be bent must be carefully studied and the bending operation must be effected outside of the mouth.
It has long been known that an implant must be anchored permanently. In addition to eliminating or minimizing void spaces in the bone tissue, the implant should be supported at both ends in the bone, that is, it must be supported by the compact bone tissue of the alveolar countercorticalis. However, as a rule, the formation of voids can only be prevented when, during the insertion of the screw implant, there is no destruction of the bone tissue through which it travels. In the case of prior known screw implants, this cannot be prevented due to the relatively deep penetration of the cutting threads. However, as a result of the destruction of tissue and the development of voids around the implant, primary stability, on which later retention depends and which is responsible for a strong bond between the implant and bone, is not ensured. Especially in the front tooth region of the lower jaw, the length of the screw implant determines the degree of support by the bone tissue against which the implant lies during insertion. Therefore, either an implant with an accurate length must be used, or the end that protrudes from the jaw (i.e. the implant post) must be shortened or ground to the proper size.


A printed millimeter wave dipole antenna and techniques for designing such an antenna are disclosed. In one embodiment, the dipole antenna comprises: a signal wing and at least one ground wing for propagating signals in a millimeter wave band; and an unbalanced feeding structure directly coupled to the signal wing. The unbalanced feeding structure is boarded by a plurality of escorting vias to ensure equipotential grounds.

The 60 GHz band is an unlicensed band which features a large amount of bandwidth and a large worldwide overlap. The large bandwidth means that a very high volume of information can be transmitted wirelessly. As a result, multiple applications, each requiring transmission of large amounts of data, can be developed to allow wireless communication around the 60 GHz band. Examples for such applications include, but are not limited to, wireless high definition TV (HDTV), wireless docking stations, wireless Gigabit Ethernet, and many others.
In order to facilitate such applications, there is a need to develop integrated circuits (ICs) such as amplifiers, mixers, radio frequency (RF) analog circuits, and active antennas that operate in the 60 GHz frequency range. An RF system typically comprises active and passive modules. The active modules (e.g., a phased array antenna) require control and power signals for their operation, which are not required by passive modules (e.g., filters). The various modules are fabricated and packaged as radio frequency integrated circuits (RFICs) that can be assembled on a printed circuit board (PCB). The size of the RFIC package may range from several to a few hundred square millimeters.
In the consumer electronics market, the design of electronic devices, and thus RF modules integrated therein, should meet be designed to minimize cost, size, power consumption, and weight. The design of the RF modules should also take into consideration the current assembled configuration of electronic devices and, particularly, handheld devices such as laptop, smartphones, and tablet computers, in order to enable efficient transmission and reception of millimeter wave signals. Furthermore, the design of the RF module should account for minimal power loss of receive and transmit RF signals as well as for maximum radio coverage.
A schematic diagram of a RF module 100 designed for transmission and reception of millimeter wave signals is shown in FIG. 1. The RF module 100 includes an array of active antennas 110-1 through 110-N connected to a RF circuitry or IC 120. Each of the active antennas 110-1 through 110-N may operate as a transmit (TX) and/or a receive (RX) antenna. An active antenna can be controlled to receive/transmit radio signals in a certain direction, to perform beam forming, and to switch between receive and transmit modes. For example, an active antenna may be a phased array antenna in which each radiating element can be controlled individually to enable the usage of beam-forming techniques.
In the transmit mode, the RF circuitry 120 typically performs up-conversion, using a mixer (not shown in FIG. 1), to convert intermediate frequency (IF) signals to radio frequency (RF) signals. Then, the RF circuitry 120 transmits the RF signals through the TX antenna according to the control signal. In the receive mode, the RF circuitry 120 typically receives RF signals through the active RX antenna and performs down-conversion, using a mixer, to IF signals using the local oscillator (LO) signals, and sends the IF signals to a baseband module (not shown in FIG. 1).
In both receive and transmit modes, the operation of the RF circuitry 120 is controlled by the baseband module using a control signal. The control signal is utilized for functions such as gain control, RX/TX switching, power level control, beam steering operations, and so on. In certain configurations, the baseband module also generates the LO and power signals and transfers such signals to the RF circuitry 120. The power signals are DC voltage signals that power the various components of the RF circuitry 120. Normally, the IF signals are also transferred between the baseband module and the RF circuitry 120.
In common design techniques, the array of active antennas 110-1 to 110-N are implemented on the substrate upon which the IC of the RF circuitry 120 is also mounted. An IC is typically fabricated on a multi-layer substrate and metal vias that connect between the various layers. The multi-layer substrate may be a combination of metal and dielectric layers and can be made of materials such as a laminate (e.g., FR4 glass epoxy, Bismaleimide-Triazine), ceramic (e.g., low temperature co-fired ceramic LTCC), polymer (e.g., polyimide), PTFE (Polytetrafluoroethylene) based compositions (e.g., PTFE/Ceramic, PTFE/Woven glass fiber), Woven glass reinforced materials (e.g., woven glass reinforced resin), wafer level packaging, and other packaging, technologies and materials. The cost of the multi-layer substrate is a function of the area of the layer—the greater the area of the layer, the greater the cost of the substrate.
Antenna elements of the array of active antennas 110-1 to 110-N are typically implemented by having metal patterns in a multilayer substrate. Each antenna element can utilize several substrate layers. In conventional implementations for millimeter wave communications, antenna elements are designed to occupy a single side of the multi-layer substrate side. This is performed in order to allow the antenna radiation to properly propagate.
For example, a millimeter wave (mm-wave) RF module 200 depicted in FIG. 2 includes a multi-layer substrate 210 and a plurality of antenna elements 220 implemented on an upper layer of the substrate 210. The antenna elements 220 are connected to a RF circuitry 230 using traces 201. The RF circuitry 230 performs the function discussed in greater detail above. The RF module 200 may also contain discrete electronic components 240 such as an antenna interface in an implementation of chip-board transition structure, which typically includes the IC (chip) package and transmission lines from the IC to the substrate. Additionally, circuits designed for impedance matching and electrostatic discharge (ESD) protection may also be part of the antenna interface.
In order to maximize the coverage of a millimeter wave RF module, the RF module operates according to the specification of the IEEE 802.11ad (also known as the WiGig), such that a large number of antennas should be included in the RF module. Some conventional RF designs require implementing a number of active antennas on one side of the substrate, thereby providing a constraint that limits the number of antennas of the RF module. Another conventional design includes placing a number of antennas on different sides of the substrate, thereby enabling the RF signal to radiate in all directions.
In both of the above noted approaches, an attempt to increase the number of active antennas would require increasing the area of substrate. Also, such an attempt would require increasing the length of the wires (traces) from the RF circuitry to the antenna elements. Further, some antennas require differential signal feeding via, e.g., a balun structure which consumes substrate area. In this case, a problem arises as some area of the substrate should be reserved for other structures, such as antenna feed lines. Any design of a RF module designed with a large number of antennas should meet the constraints of an efficient design. Such constraints necessitate that the physical dimensions, power consumption, heat transfer, and cost be minimized whenever possible.
Typically, the antennas that require differential signal feeding via, e.g., a balun structure, are dipole and Yagi-types antennas. More specifically, a dipole antenna is typically fed by two arms that are 180° out of phase with respect to each other. The arms must have equal electric field amplitude distribution. When a dipole is fed from an unbalanced source (unequal field distribution), such as a coax or microstrip, a balun is used to transition the source transmission line from an unbalanced state to a balanced state. The balanced transmission line is generally in the form of a two-wire line.
Additionally, when fed over a ground plane, a dipole antenna needs to be on the order of a quarter-wavelength from the ground so that the dipole is not shorted to the ground plane.
In existing solutions, the feed line from the ground to the dipole is typically designed using a balanced line. The balun is implemented in an earlier stage of the antenna as a separate component. This requires more space and line length, which are disadvantages in a system that is space limited. Other solutions use the quarter wavelength section from the ground as a matching section and part of the balun. However, this type of balun cannot support a broadband frequency range.
Another design constraint that should be considered when providing an RF module with a large number of millimeter-wave antennas is the connection of an antenna to multiple amplifiers for increased transmission power and/or reception sensitivity. Typically, such a connection requires an extra circuit element: a power combiner. The power combiner can be in the form of a simple T-junction or a more complex Wilkinson divider. In either case, extra line length and circuitry must be added for the combiner and any associated matching network. As a result, a problem arises with such designs as the area of the substrate is limited and should be reserved for other structures. Thus, an attempt to increase the number of antennas in a mm-wave RF module while meeting the above-noted constraints would significantly increase the area of the module's substrate and, therefore, reduce the efficiency of the RF module.
It would be therefore advantageous to provide an efficient design for mm-wave antennas that overcomes the disadvantages noted above.

Techniques for designing millimeter wave printed dipole antennas


An electromagnetic cooling fan includes a thin blade connected to an elongated beam. The beam is simply supported at its two ends with two supporting members. The beam has a magnet attached to it at the center. An electromagnet is used to generate cyclic force on the magnet, causing the beam and the blade to oscillate, generating air flow for cooling purpose.

Many components in an electronic package such as CPU, GPU, and LED light dissipate significant heat during operation, which causes temperature increase in the package. This may negatively affect user experience, performance and reliability of the package. A rotary fan blowing air across high temperature regions is usually used for cooling purpose. Rotary fans can generate significant air flow. However, they are relatively unreliable due to their bearing system.
Another type of fan is flapping fan, which typically includes an elongated cantilever blade attached to an actuator. Flapping fans can be driven by either piezo actuators (as seen in, for example, U.S. Pat. Nos. 4,595,338, 4,780,062, 4,923,000, 5,861,703, 7,061,161, 7,642,698, U.S. 20020175596 A1, U.S. 2007/0090726 A1, U.S. 2011/0120679 A1, U.S. 2011/0014069 A1, U.S. Pat. Nos. 8,322,889, and 8,581,471) or electromagnetic ones (as seen in, for example, U.S. Pat. No. 6,043,978 A, U.S. 2016/0320812 A1, U.S. 2017/0181316 A1). Since flapping fans include no moving parts, they are very reliable. Unfortunately, aerodynamic efficiency of the fans is usually low. They generate very little net air flow, which greatly limits their applications.
Accordingly, the need still exists for a fan that is reliable, efficient, and able to generate significant net air flow for cooling purpose.


Phenylenediamines represented by general formula (1): ##STR1## wherein R represents an alkyl group or an optionally substituted aralkyl group, X.sup.1 represents a hydrogen atom or a halogen atom, and X.sup.2 represents a halogen atom; salts thereof, and a process for preparing the same. The compounds are useful as intermediates for synthesis of pyridonecarboxylic acid derivatives useful as antibacterial agents.

Among compounds having a basic skeleton of pyridonecarboxylic acid there have been known a variety of compounds useful as synthetic antibacterial agents, since they have excellent antibacterial activity and a wide antibacterial spectrum. Of these, in the clinical field, as therapeutic agents for infectious diseases there have been widely used compounds such as norfloxacin (Japanese Patent Application Laid-Open (kokai) No. 53-141286), enoxacin (Japanese Patent Application Laid-Open (kokai) No. 55-31042), ofloxacin (Japanese Patent Application Laid-Open (kokai) No. 57-46986), ciprofloxacin (Japanese Patent Application Laid-Open (kokai) No. 58-76667), and tosufluoxacin (Japanese Patent Application Laid-Open (kokai) No. 60-228479).
However, these compounds are not perfectly satisfactory in terms of antibacterial activity, intestinal absorption efficiency, stability in metabolism, and side effects, inter alia, phototoxicity and cytotoxicity.
In view of the foregoing, an object of the present invention is to provide pyridonecarboxylic acid-based antibacterial agents which have satisfactory antibacterial activity, intestinal absorption efficiency, stability in metabolism, and acceptable side effects particularly in terms of phototoxicity and cytotoxicity; and to provide intermediates for synthesis thereof.

Phenylenediamines and process for preparing the same


A projectile launcher includes a barrel mount, a tubular barrel, and a biasing member disposed in the barrel. The barrel mount can assume a barrel-securing configuration and a barrel-releasing configuration in which the barrel is longitudinally movable relative to the barrel mount from a forward position to a rearward position. The biasing member is compressible from an initial relaxed position to a first compressed position with the barrel in the rearward position, and to a second (further) compressed position the barrel in the forward position. The projectile can thus be launched at different speeds according to the barrel position. The launcher may also include a trigger release, a handgrip, and indicia markings on the barrel to denote approximate launch distance or other information. Optionally, the projectile is attached to a lead line that loops over a tree branch upon launching, such as for suspending a food container at a campsite.

For purposes of safely storing food bags or containers in wilderness areas, such as during camping activities, it is known to tie a cord to a rock and manually throw the rock over a tree branch. If done correctly, the rock will loop over the branch, carrying the cord with it, and then dangle from the branch. The user can then pull down on the cord to raise a food bag sufficiently high above the ground so that a bear or other animal cannot access the bag from the ground. However, it can take many attempts to loop a cord over a desired branch in this manner, as the rock can easily come untied from the cord, and it can be very difficult to manually throw the rock substantially vertically so as to loop over a desired branch without missing or catching on other branches.


Methods of administering an injection are provided including methods of administering injections by individuals exhibiting deteriorated motor skills or impaired hand function. The method includes establishing a hand position about an injection device, including placing at least a one digit of a user' hand about the injection device and placing at least one other digit of a user's hand upon an actuator of the injection device. The hand position is substantially maintained while the injection device is manipulated and positioned to insert a needle at one end thereof into a portion of the user's skin. The hand position is substantially maintained while the user displaces the actuator of the injection device with the at least one other digit in a direction which is substantially transverse to an axis defined between a first end of the injection device and a second end of the device, the needle being located at the second end of the device.

Numerous injection devices are available for the administration of various medical, pharmaceutical and cosmetic fluid products, including, for example, administration of insulin, and growth hormones. Such injection devices include so-called injection pens (or pen injectors) which are generally shaped and configured like a large pen and are conventionally utilized for self-administered injections. Injection pens may comprise a casing or housing in which is disposed the fluid to be administered. Such fluid is often contained in a second housing, such as a carpoule (also referred to as an ampoule), which may be removable and replaceable with respect to the injector housing. An injection needle or cannula may be placed in communication with the fluid product and configured to deliver the fluid product therethrough upon actuation of the injection device. The injection device may additionally include various mechanisms disposed within the injector housing which enable the administration of the fluid product through the needle in accordance with one or more specified requirements.
For example, a known mechanism for dispensing the fluid product from the container includes a manually deployed actuator that causes displacement of the fluid product from its associated container through the associated needle. Additionally, many injection devices include a mechanism for user adjustment of the dosage or volume of material which is to be delivered through the needle upon deployment of the dispensing actuator. In other injection devices, the dosage may be pre-set or predetermined such that a consistent volume of fluid product is dispensed each time the dispensing actuator is deployed or triggered. A mechanism may be configured to indicate, for example, a selected dosage, a cumulative total of fluid product which has been dispensed from a given container, or a residual amount of the product still remaining in the container. A conventional injection device which includes some of the above listed features is disclosed in U.S. Pat. No. 5,279,586 to Balkwill.
Many conventional injection devices, including those disclosed by the Balkwill patent, have manual actuating mechanisms that require displacement thereof in a direction that is collinear with a longitudinal axis of the injection device's housing. In other words, the actuator is often disposed at an end of the injection device opposite the needle or cannula and must be displaced in a direction towards the needle or cannula in order to effect dispensing of a fluid product. Thus, in operation, such conventional devices are often grasped in the palm of a user's hand with the user's fingers wrapping therearound to form a fist. The user may then position the injection device so as to insert the needle into the user's skin in anticipation of delivering the fluid product. The actuator of the device is then displaced by application of force thereto by a user's thumb. Alternatively, a user may grasp such an injection device between his or her thumb and at least one finger, such as their middle finger, and then displace the actuator with his or her forefinger. In either case, the displacement of the actuator at the end of the injection device can be awkward and difficult for many individuals.
For example, elderly individuals or individuals with impaired hand function may lack the dexterity, motor skills, strength, or a combination thereof, to actuate the injection device while maintaining a firm grasp. Thus, individuals with arthritis or some other ailment affecting the use of their hands may have considerable difficulty in administering therapeutic injections. Ultimately, the difficulty in administering such injections may result in noncompliance by a user with regard to the regular administration of injections in accordance with a prescribed treatment.
Another injection device which employs a different actuation mechanism configuration is disclosed in U.S. Pat. No. 5,584,815 to Pawelka et al. The Pawelka patent generally discloses an injection device having a wing member extendable from one side, wherein pivotal displacement of the wing actuates a dispensing mechanism for delivery of a fluid product through its associated needle and also resets a dosage indicator to an initial zero position. Thus, in operation, a user clasps the circumference of the injection apparatus and pushes the wing into the interior of the apparatus, such that it is angularly displaced about a pivot or fulcrum point.
However, the device disclosed in the Pawelka patent may be prone to an inadvertent discharge or dispensing of fluid during the act of inserting the needle into a user's skin. For example, since the fulcrum of wing actuator is designed such that a user's hand will be positioned between the fulcrum of the wing and the needle during operation, a user may inadvertently displace the wing while grasping the injection device and applying a force in the direction of the needle, as is required to insert the needle into the user's skin. Thus, the user of the device may not receive the proper amount of fluid during the injection, as some fluid become lost during the inadvertent displacement of the wing. While it is recognized that a user may position their hand at a different location during insertion of the needle and then reposition their hand after such insertion, such a process may be laborious and difficult for those with poor motor skills or those that exhibit impaired hand function.
In view of the shortcomings in the art, it would be advantageous to provide a method and device which enables individuals with poor motor skills or with impaired hand function to consistently administer injections in a safe, simple, and accurate manner. It would further be desirable to provide such a method and device which minimize the number of actions required by the user and simplifies the injection process.

Methods of administering therapeutic injections


A rotary mixing device provides an elongate powering shaft carrying at a first end portion mixing apparatus formed by a first outer annulus interconnected by quadrantally arrayed first radial elements to the first end portion of the powering shaft, and a second inner annulus spacedly distant along the powering shaft from the first annulus and having quadrantally arrayed second radial elements interconnecting the second annulus and the powering shaft, with each of the second radial elements of the second annulus being coplanar with one of the first radial elements of the first annulus. Elongate peripheral elements extend in quadrantal array to interconnect the first and second annuli with end portions immediately radially outwardly from each coplanar pair of first and second radial elements. The elements of the mixing device and the powering shaft are formed of rigid rod-like material having a circular cross-section of substantial area such that the volume of the mixing device comprises from ten to twenty percent of the volume defined by a figure that would contain the mixing device in an immediately adjacent relationship.

RELATED APPLICATIONS
There are no applications related hereto heretofore filed in this or any foreign country.
1. Field of Invention
This invention relates generally to rotary mixing apparatus, and more specifically to such an apparatus that is peripherally defined by elongate cylindrical elements that have substantial cross-sectional area perpendicular to their rotational direction to create turbulence upon rotation.
2. Background and Description of Prior Art
Apparatus moved by a powered rotating shaft has long been known for mixing fluidic, semi-fluidic (viscous) and quasi-fluidic (containing solid particles) materials to form a more homogenous mixture. Such apparatus has taken many and various forms determined primarily by the configuration of the mixing apparatus, the nature of the material being admixed and the rotational speed of the apparatus. Though the historical developmental period of such mixing apparatus has been long and throughout that period the apparatus developed has become increasingly sophisticated, problems still remain with such apparatus, and especially in any generic type of apparatus that well and efficiently mixes both low viscosity fluids and more highly viscous semi-fluid and quasi-fluid materials. The instant device provides a mixing apparatus, usable in a wide variety of materials and through a wide range of rotary speeds, with substantial efficiency.
Rotary mixing apparatus may be divided into two generalized classes for ease of consideration, with a first class comprising devices intended to mix more fluidic materials generally at relatively higher rotary speeds and a second class intended to mix more viscous semi-fluidic material or quasi-fluidic material containing particulate matter at slower speeds.
The first class of mixing apparatus generally provides a plurality of interconnected elements, usually of circularly symmetrical array and generally of smaller cross-sectional area in a plane perpendicular to the direction of rotation than do mixing devices of the second class. Such configuration allows more rapid rotation of the mixing apparatus without excessive force on any of the rotating elements and allows sufficient rotary speed to create a vortical type configuration in a fluid being admixed without ejecting the fluid from a container that is not of substantially greater volume than the fluid. The vortical type action of such mixers is considered by most users to provide a better and more rapid mixing of the components of a mixture to create a homogenous product. Such mixers, however, are not practical or efficient for mixing viscous semi-fluidic material or quasi-fluidic material containing particulate matter, as their structure is not strong enough to allow rapid rotation and the size of the mixing elements is not great enough to create sufficient material friction and motion for proper mixing. Additionally this first class of apparatus generally has a circularly symmetrical structure to promote rotation at higher speeds without excessive vibrations which normally cannot be completely restrained and this, especially when coupled with small cross-sectional size of the elements, further reduces the efficiency of mixing of viscous material.
Rotary mixers of the second class generally are rotated at lower speeds and present cross-sectional patterns of greater areal extent in a plane perpendicular to the direction of rotation of the mixer, so as to create motion in the material adjacent to the mixer elements relative to the material spacedly adjacent thereto which causes motion in the relatively moving portions of material to more efficiently and effectively accomplish the mixing function.
Generally the members of this second class of apparatus have provided flat blade-like elements, often particularly shaped to aid their function, that are of substantial area. Such blade-like elements often are angulated to a plane perpendicular to their direction of rotation to allow rotation at a higher speed and to direct the motion of material impinging thereon in a more efficient mixing action. Since these devices rotate at relatively slower speeds than apparatus of the first class, it is not necessary that they be of so symmetrical a nature as higher speed devices of the first class and often an asymmetrical configuration has been used to enhance the mixing action of the second class of mixing apparatus.
The instant device combines features of both the first and second class of mixing apparatus described to provide a new mixing device that functions equally well at higher speeds in more fluidic, lower viscosity materials and also at slower speeds in more viscous semi-fluidic and quasi-fluidic materials.
To accomplish these ends a mixer structure formed of interconnected areally larger rod elements of circularly symmetrical array is provided. The rod elements are spatially arrayed so that when the structure is rotated some elements move in each of three mutually perpendicular planes to maximize their mixing function. The cross-sectional size of the elements in a plane perpendicular to their direction of rotation is substantially greater than that of wire-like elements that have heretofore been used in rotary mixing devices for fluidic material of low viscosity. The instant elements allow the mixing of low viscosity fluids at speeds that create a vortical motion and tend to enhance that mixing by the creation of greater fluidic friction and turbulence about the interface of the moving elements and fluid being mixed with greater motion of the fluid surrounding the moving elements relative to the fluid more distant therefrom to accelerate and make more efficient the mixing action. The mixing action is also enhanced at lower rotary speeds in more viscous mixtures where the curvilinear shape of the moving elements allow higher speeds than normally attained in prior viscous material mixers, so that the mixing action of the larger surface and cross-sectional areas and higher rotary speeds synergistically combine to provide a more efficient and rapid mixing action for viscous materials.
My invention resides not in any one of these features individually, but rather in the synergistic combination of all of the structures of my mixing device that necessarily give rise to the functions flowing therefrom.

Rotary mixing device for fluidic material


Analogs of human erythropoietin, including the X.sup.33, Cys.sup.139, des-Arg.sup.166 ! and Cys.sup.139, des-Arg.sup.166 ! analogs, as well as methods for making and using such analogs and pharmaceutical compositions containing the same.

Erythropoietin is a naturally-occurring glycoprotein hormone with a molecular weight that was first reported to be approximately 39,000 daltons (T. Miyaki et al., J. Biol. Chem. 252:5558-5564 (1977)). The mature hormone is 166 amino acids long and the "prepro" form of the hormone, with its leader peptide, is 193 amino acids long (F. Lin, U.S. Pat. No. 4,703,008). The mature hormone has a molecular weight, calculated from its amino acid sequence, of 18,399 daltons (K. Jacobs et al., Nature 313:806-810 (1985); J. K. Browne et al., Cold Spring Harbor Symp. Quant. Biol. 51:693-702 (1986)).
Structural characterization of human urinary erythropoietin has identified a des-Arg166 form that results from specific removal of the Arg residue at the carboxy-terminus of the mature protein (M. A. Recny et al., J. Biol. Chem. 262:17156-17163 (1987)). Recny et al., supra, propose that the physiologically active form of erythropoietin circulating in human plasma is the des-Arg166 form.
Human erythropoietin contains three N-linked carbohydrate chains (H. Sasaki et al., J. Biol. Chem. 262:12059-12076 (1987); E. Tsuda et al., Biochemistry 27:5646-5654 (1988); and M. Takeuchiet al., J. Biol. Chem. 263:3657-3663 (1988)). The carbohydrate content of erythropoietin is similar in both naturally-occurring urinary erythropoietin and in hormone produced by expression, in mammalian cells in culture, of a cloned DNA which has been transfected into the cells and which encodes the prepro form of the hormone. The N-linked glycosylation sites are located at amino acid residues 24, 38, and 83. Both urinary and recombinant erythropoietin also contain a single O-linked glycosylation site at amino acid residue 126 (H. Sasaki et al., supra; E. Tsuda et al., supra; M. Takeuchi et al., supra; and M. Goto et al., Biotechnology 6:67-71 (1988)). The carbohydrate content of erythropoietin is a complex fucosylated tetra antennary type chain with and without N-acetyllactoseamine repeating units (M. Takeuchi et al., supra) and contributes approximately 40% of the mass of erythropoietin.
Human erythropoietin is primarily produced as a glycoprotein hormone by the adult kidney (H. P. Koeffler and E. Goldwasser, Ann. Intern. Med. 97:44-47 (1981)). The cells that produce erythropoietin in the kidney are rare and are located in the inner cortex of the renal parenchyma in the intersticium between renal tubules (S. T. Koury et al., Blood 71:524-528 (1988), and C. Lacombe et al., J. Clin. Invest. 81:620-623 (1988)). Consequently, destruction of kidney tissue, as occurs in renal failure, results in decreased production of erythropoietin and a concomitant reduction in erythrocyte count and anemia.
While fetal liver cells in vitro can produce erythropoietin (A. Kurtz et al., Endocrinology 118:567-572 (1986)), no compensating erythropoietin production occurs in most end-stage renal failure patients, and serum erythropoietin levels are normally restored only after successful renal transplantation (W. F. Denny et al., J. Lab. Clin. Med. 67:386 (1966)).
Late stage erythropoiesis, in most cases, is accomplished by a single glycosylated hormone, erythropoietin, produced in a single tissue. A rare alternate route of erythropoiesis has been documented in a human anephric patient with a high hematocrit. The isolated erythrotropic factor in this patient has been shown to be human insulin-like growth factor 1, or IGF-I (A. Brox et al., Exp. Hematol. 17:769-773 (1989), and L. F. Congote et al., J. Clin. Endocrin. Metab. 72:727-729). IGF-I is undoubtedly the human counterpart of the bovine erythrotropic factor described as having both in vivo and in vitro activity by L. F. Congote (Biochem. Biophys. Res. Comm. 115:477-483 (1983)). IGF-I receptors are known to exist on human erythrocytes, and these receptors could allow this rare alternate route of late stage erythropoiesis to occur via interaction of IGF-I and its specific receptor (T. Izami et al., J. Clin. Endocrinol. Metab. 62:1206-1212 (1986), and C. D. Costigan et al., Clin. Invest, Med. 11:4751 (1988)). However, the nucleotide sequence of the erythropoietin receptor gene is known and shows no sequence homology to that of the human IGF-I receptor (A. D. D'Andrea et al., Cell 57:277-285 (1989)), indicating that the alternate route of erythropoiesis via IGF-I is unrelated to the erythropoietin-mediated pathway of late stage erythropoiesis.
While no other alternate routes of late stage erythropoiesis are known, several factors have been described that can potentiate the action of erythropoietin. Late stage erythropoiesis is dependent on erythropoietin but is influenced by testosterone, estrogens, and erythroid-potentiating factor, while the early stage of erythropoiesis is dependent on burst-promoting activity in addition to erythropoietin (N. N. Iscove in Hematopoietic Cell Differentiation, eds. D. W. Golde, M. J. Cline and C. F. Fox Academic Press, New York! pp. 37-52). Factors such as IL-3, granulocyte macrophage colony-stimulating factor and interleukin-9 are known to have burst-forming activity. However, it is unclear whether these activities have any physiological role in erythropoiesis (J. Suda et al., Blood 67:1002-1006 (1986); C. A. Sieff et al., Science 230:1171-1173 (1985); and R. E. Donahoe et al., Blood 75:2271-2275 (1989). Recently, a factor termed "erythroid differentiation factor" has been shown to potentiate the activity of erythropoietin in vivo and in vitro (H. E. Broxmeyer et al., Proc. Natl. Acad. Sci. 85:9052-9056 (1988); J. Yu et al., Nature 330:765-767 (1987)). This factor has been shown to be identical to activin A (follicle-stimulating hormone-releasing protein) and to be inhibited by follistatin, a specific inhibitor of activin A; however, the physiological role of activin A remains to be determined (M. Shiozaki et al., Proc. Natl. Acad. Sci. 89:1553-1556 (1992)). Thus, after nearly twenty years of investigation, there is no clear indication that erythropoiesis is controlled by any hormone other than erythropoietin.
In the absence of any alternative hormones which affect erythropoiesis, several attempts to both probe erythropoietin structure and significantly improve the characteristics of erythropoietin by site-directed mutagenesis have appeared in the literature. The molecular cloning of the human gene encoding erythropoietin reveals a DNA sequence coding for a preprohormone of 193 amino acids and a mature hormone of 166 amino acids. The availability of cloned DNA encoding the hormone and its precursor (i.e., the prepro form) provides the opportunity for mutagenesis by standard methods in molecular biology. See U.S. Pat. No. 4,703,008, supra.
The first mutant erythropoietins (i.e., erythropoietin analogs), prepared by making amino acid substitutions and deletions, have demonstrated reduced or unimproved activity. As described in U.S. Pat. No. 4,703,008, replacement of the tyrosine residues at positions 15, 49 and 145 with phenylalanine residues, replacement of the cysteine residue at position 7 with an histidine, substitution of the proline at position 2 with an asparagine, deletion of residues 2-6, deletion of residues 163-166, and deletion of residues 27-55 does not result in an apparent increase in biological activity. The Cys.sup.7 -to-His.sup.7 mutation eliminates biological activity. A series of mutant erythropoietins with a single amino acid substitution at asparagine residues 24, 38 or 83 show severely reduced activity (substitution at position 24) or exhibit rapid intracellular degradation and apparent lack of secretion (substitution at residue 38 or 183). Elimination of the 0-linked glycosylation site at Serinel26 results in rapid degradation or lack of secretion of the erythropoietin analog (S. Dube et al., J. Biol. Chem. 33:17516-17521 (1988)). These authors conclude that glycosylation sites at residues 38, 83 and 126 are required for proper secretion and that glycosylation sites located at residues 24 and 38 may be involved in the biological activity of mature erythropoietin.
The suggestion that glycosylation of erythropoietin is required for in vitro biological activity is contrary to reports showing that deglycosylatjed erythropoietin is fully active in vitro bioassays (M. S. Dordal et al., Endocrinology 116: 2293-2299 (1985); J. K. Browne et al., Cold Spring Harbor Symp. Quan. Biol. 51:693-702 (1986); U.S. Pat. No. 4,703,008; E. Tsuda et al., Eur. J. Biochem. 188:405-411 (1990); and K. Yamaguchi, et al., J. Biol. Chem. 266:20434-20439 (1991)). A set of analogs of erythropoietins, similar to those studied by Dube et al., supra, has been constructed using oligonucleotide-directed mutagenesis to probe the role of glycosylation sites in the biosynthesis and biological activity of erythropoietin (K. Yamaguchi et al., supra). These investigators conclude that glycosylation is important for the correct biosynthesis and secretion of erythropoietin but has no affect on the in vitro activity of the molecule. However, all of the mutant erythropoietins studied by Yamaguchi et al., which involve changes at the glycosylation sites, lack in vivo biological activity.
Glycosylation of erythropoietin is widely accepted to play a critical role in the in vivo activity of the hormone (P. H. Lowy et al., Nature 185:102-105 (1960); E. Goldwasser and C. K. H. Kung, Ann. N.Y. Acad. Science 149:49-53 (1968); W. A. Lukowsky and R. H. Painter, Can. J. Biochem. 50:909-917 (1972); D. W. Briggs et al., Amer. J. Phys. 201:1385-1388 (1974); J. C. Schooley, Exp. Hematol. 13:994-998; N. Imai et al., Eur. J. Biochem. 194:457-462 (1990); M. S. Dordal et al., Endocrinology 1 16:2293-2299 (1985); E. Tsuda et al., Eur. J. Biochem. 188:405-411 (1990); U.S. Pat. No. 4,703,008; J. K. Brown et al., Cold Spring Harbor Symposia on Quant. Biol. 51:693-702 (1986); and K. Yamaguchi et al., J. Biol. Chem. 266:20434-20439 (1991)).
The lack of in vivo biological activity of deglycosylated analogs of erythropoietin is attributed to a rapid clearance of the deglycosylated hormone from the circulation of treated animals. This view is supported by direct comparison of the plasma half-life of glycosylated and deglycosylated erythropoietin (J. C. Spivak and B. B. Hoyans, Blood 73:90-99 (1989), and M. N. Fukuda, et al., Blood 73:84-89 (1989).
Oligonucleotide-directed mutagenesis of erythropoietin glycosylation sites has effectively probed the function of glycosylation but has failed, as yet, to provide insight into an effective strategy for significantly improving the characteristics of the hormone for therapeutic applications.
A series of single amino acid substitution or deletion mutants have been constructed, involving amino acid residues 15, 24, 49, 76, 78, 83, 143, 145, 160, 161, 162, 163, 164, 165 and 166. In these mutants are altered the carboxy terminus, the glycosylation sites, and the tyrosine residues of erythropoietin. The mutants have been administered to animals while monitoring hemoglobin, hematocrit and reticulocyte levels (European Published Patent Application No. 0 409 113). While many of these mutants retain in vivo biological activity, none show a significant increase in their ability to raise hemoglobin, hematocrit or reticulocyte (the immediate precursor of an erythrocyte) levels when compared to native erythropoietin.
Another set of mutants has been constructed to probe the function of residues 99-119 (domain 1) and residues 111-129 (domain 2) (Y. Chern et al., Eur. J. Biochem. 202:225-230 (1991)). The domain 1 mutants are rapidly degraded and inactive in an in vitro bioassay while the domain 2 mutants, at best, retain in vitro activity. These mutants also show no enhanced in vivo biological activity as compared to wild-type, human erythropoietin. These authors conclude that residues 99-119 play a critical role in the structure of erythropoietin.
The human erythropoietin molecule contains two disulfide bridges, one linking the cysteine residues at positions 7 and 161, and a second connecting cysteines at positions 29 and 33 (P.-H. Lai et al., J. Biol. Chem. 261:3116-3121 (1986)). Oligonucleotide-directed mutagenesis has been used to probe the function of the disulfide bridge linking cysteines 29 and 33 in human erythropoietin. The cysteine at position 33 has been converted to a proline residue, which, mimics the structure of murine erythropoietin at this residue. The resulting mutant has greatly reduced in vitro activity. The loss of activity is so severe that the authors conclude that the disulfide bridge between residues 29 and 33 is essential for erythropoietin function (F.-K. Lin, Molecular and Cellular Aspects of Erythropoietin and Erythropoiesis, pp. 23-36, ed. I. N. Rich, Springer-Verlag, Berlin (1987)).
Site-specific oligonucleotide-directed mutagenesis of the methionine residue at position 54 of human erythropoietin results in a molecule which retains the in vivo biological activity of the parent (wild-type) molecule with the added advantage of providing an erythropoietin preparation which is less susceptible to oxidation (Shoemaker, U.S. Pat. No. 4,835,260).
A large number of mutants of the human erythropoietin gene have been described in several scientific publications and patent applications. These mutants have spanned the entire length of the molecule, have produced partially- or completely-deglycosylated molecules, have altered the structures of the disulfide bridges in the molecule, and have attempted to improve the therapeutic activity of the molecule. Of all such attempts to alter erythropoietin, none have succeeded in producing a molecule with enhanced in vivo biological activity or other improved properties for therapeutic applications.
The failure to identify a naturally-occurring alternate route of late stage erythropoiesis and the heretofore unsuccessful attempts to produce an erythropoietin analog with enhanced in vivo activity have provided little insight into how an improved erythrotropic molecule could be made.

DNA encoding human a erythropoietin analog


The bottom of a dip coating bath (5a) is perfluoro(methylcyclohexane), a dense, inert liquid. A much thinner layer of coating solution occupies the top (5b) of the bath. An aluminum drum (1) to be coated is moved into the bottom bath until the top of the drum is in the top of the bath. The drum is moved out of the bath and is coated by the top liquid. The amount of coating material used is greatly reduced and the inert liquid can be reused.

Known dip coating is by immersing the item to be coated in a bath consisting entirely of the coating and moving the item out of the bath. A meniscus naturally forms between the bath and the item, and a coating of the bath material clings to the item. To coat, for example, a cylinder, the cylinder is oriented with its long axis vertically and is moved down into the bath and then upward out of the bath. As it leaves the bath, it is coated with the bath material.
Where the bath chemically deteriorates with the passage of time or by contamination from items immersed or the atmosphere, it is discarded and replaced by a new bath. This invention may employ standard coating apparatus but significantly limits the amount of bath material which is subject to such discharge. This invention employs a ring of coating material floating on a column of noncoating material. Example 1 of U.S. Pat. No. 5,683,742 to Herbert et al. has a film of coating material sprayed on water.


The present invention is a composite material, a process and a product formed by the process. The composite is formed by a process that includes forming a fibrous structure comprising fibers into a preform, coating the fibers of the fibrous structure preform with elemental carbon to impregnate that preform, infiltrating the preform with boron carbide to form an impregnated green body. The impregnated green body is infiltrated with liquid naphthalene or other carbon precursor, which is thereafter pyrolyzed to form a carbon char. Then, the char infiltrated green body is infiltrated with molten silicon to form a continuous matrix throughout the composite. The silicon in the continuous matrix is reacted with the carbon char to form silicon carbide.

Current aircraft braking systems utilize either steel or carbon disks that serve as the friction materials and heat sinks. Steel-based systems were originally used as brake materials, until the emergence of carbon-carbon (C—C) composite materials in the 1970s. C—C composites are now the state-of-the-art material for aircraft brake heat sinks and are being used in the vast majority of new military and large commercial aircraft programs.
Ceramic Matrix Composites (CMCs) exhibit some extraordinary thermal and mechanical properties and hold the promise of being outstanding materials for aircraft brake friction applications, as well as attractive candidates for the next generation heat sink materials for such applications. A particular CMC system that indeed possesses the potential for use as a next generation aircraft brake material, and offers potential breakthrough performance, has recently been identified. In particular, brake materials based on a boron carbide matrix composite melt infiltration system have been shown to offer extremely attractive benefits relative to both steel and carbon brake materials.
As a class of materials, ceramics are known to possess low density in comparison to steel and other metal alloys, high hardness and high oxidation resistance; some of them also have attractive heat capacity and thermal conductivity. Compared to the C—C used today, ceramics have the potential of providing some key performance advantages in terms of reduced wear rate, enhanced oxidation resistance, and reduced heat sink weight and/or volume.
The earliest attempts to use using ceramics for aircraft braking system applications were based on monolithic ceramics and cermets. However, none of these attempts were successful. The major cause for the resultant failures was due to the inadequate mechanical properties, especially low impact resistance and low fracture toughness, in conjunction with the well-known characteristic brittleness of ceramics. Thus, activities on the next-generation heat sink materials for aircraft braking system applications have focused on the development of fiber-reinforced CMCs that would improve the fracture toughness and impact resistance (reducing the brittleness) while retaining the other advantages of ceramics.
The two prime candidate CMC material systems, identified for aircraft braking system heat-sink applications due to thermo-mechanical considerations, are based on silicon carbide (SiC) and boron carbide (B4C). Between these two material systems, the B4C-based CMCs have the particular attractions that B4C is the third hardest material known, with only diamond and cubic boron nitride being harder, and that it has a heat capacity greater than both SiC and carbon. However, B4C-based fiber-reinforced CMCs suitable for aircraft brake application had not been made due to processing difficulties associated with B4C. Generally, previous attempts to make B4C-based CMCs were limited to materials without fiber reinforcements. For example, U.S. Pat. No. 5,878,849 issued Mar. 9, 1999, describes a cermet material made by infiltrating a pressed preform of B4C powder (not filament or fiber) with aluminum.
Silicon-filled CMCs have been reported in both U.S. and foreign literature to show improved friction coefficients and/or wear life in certain configurations. See, for example: R. W. Froberg and B. A. Grider, "High Friction Carbon/Carbon Aircraft Brakes", 40th Int. SAMPE Symp., May 8 11, 1995, extended abstracts, pp 942-944; R. W. Froberg and T. E. Pratt, "Brake System with Improved Brake Material", U.S. Pat. No. 4,815,572 issued Jul. 24, 1987 (assigned to Parker Hannifin Corp); W. Krenkel, "CMC Materials for High Performance Brakes", ISTA Conference on Supercars, Aachen, 31 Oct.-4 Nov. 1994 (paper from the German Aerospace Research Establishment Institute of Structures and Design), Stuttgart; A. Lacombe, "Friction System Using Refractory Composite Material", U.S. Pat. No. 5,007,508 issued Apr. 15, 1991 (assigned to SEP, France).
In 1994, the German Aerospace Research Establishment reported sub-scale dynamometer results on a C—C+SiC composite which showed improved stability, lower wear, and shorter processing times than C—C materials. (See W. Krenkel, ibid.) Pyrolyzed resin impregnated carbon fiber preforms, infiltrated with Si at 1500° C., yielded composites containing ˜35% SiC by weight. Friction coefficients varied between 0.2 and 1.0, higher than for C—C under comparable conditions, increasing with decreasing velocity. Wear was not affected by temperature up to 900° C.
Lower net wear rates as compared to two carbon-carbon disks wearing against each other were disclosed in U.S. Pat. No. 5,007,508 covering aircraft brakes in which a C—C composite disk is worn against a disk containing carbon or SiC fibers and the CVI matrix consists of SiC as the principal phase with minor amounts of C or BN on the fibers.
While the foregoing examples illustrate the potential advantages of Si-based CMC's, few of these claims have been independently substantiated. Very often, the friction and wear (F&W) test duty cycle, including load, pressure, or length of testing time and number of cycles were either not reported, or were far less severe than those demanded under realistic aircraft braking conditions. Furthermore, many of these examples only cited either the friction or the wear results, by themselves, instead of the more relevant combined F&W data.
Certain CMC systems are disclosed in a series of U.S. patents issued to Singh et al., assigned to The General Electric Company. Those patents all disclosed the use, inter alia, of carbon fiber preforms, and in some embodiments the use of boron carbide is described. These General Electric patents fall generally into one of two groups. Some of these patents describe the production of solid state sintered ceramic bodies, wherein the composite matrix is densified by hot-press sintering, and where the final sintered body is reduced in size from the body before sintering. Those patents, generally unsuitable for producing complex, near-net shape ceramic matrix components, are: U.S. Pat. No. 4,886,682, "Process for Producing a Filament-Containing Composite in a Ceramic Matrix", issued Dec. 12, 1989; U.S. Pat. No. 4,915,760, "Method of Producing a Coated Fiber-Containing Composite", issued Apr. 10, 1990; U.S. Pat. No. 4,931,311, "Method of Obtaining a Filament-Containing Composite with a Boron Nitride Coated Matrix", issued Jun. 5, 1990; U.S. Pat. No. 5,051,301, "Coated Fiber-Containing Composite", issued Sep. 24, 1991; U.S. Pat. No. 5,067,998, "Fibrous Material-Containing Composite", issued Nov. 11, 1991; U.S. Pat. No. 5,160,676, "Fibrous Material-Containing Composite", issued Nov. 3, 1992; and U.S. Pat. No. 5,407,734, "Fiber-Containing Composite", Apr. 18, 1995.
The other General Electric patents, as referred to above, disclose the infiltration of a porous body with a molten silicon infiltrant. These patents require that the fibrous materials are coated entirely with boron nitride to avoid a reaction and bonding between the silicon infiltrant and the fibrous material, and to retain fiber pull-out capabilities and fracture toughness. Those patents are U.S. Pat. No. 4,889,686, "Composite Containing Coated Fibrous Material", issued Dec. 26, 1989; U.S. Pat. No. 4,944,904, "Method of Obtaining a Fiber-Containing Composite", issued Jul. 31, 1990; U.S. Pat. No. 4,981,822, "Composite Containing Coated Fibrous Material", issued Jan. 1, 1991; U.S. Pat. No. 5,021,367, "Fiber-Containing Composite", issued Jun. 4, 1991; U.S. Pat. No. 5,043,303, "Filament-Containing Composite", issued Aug. 27, 1991; U.S. Pat. No. 5,330,854, Filament-Containing Composite", issued Jul. 19, 1994; U.S. Pat. No. 5,376,427, "Ceramic Composite Containing Coated Fibrous Material", issued Dec. 27, 1994; U.S. Pat. No. 5,387,299, "Ceramic Composite Containing Coated Fibrous Material", issued Feb. 7, 1995; and U.S. Pat. No. 5,432,253, "Composite Containing Fibrous Material", issued Jul. 11, 1995.
In summary, prior to the present invention, there was no known practical processing technique for producing dense, fiber-reinforced B4C based CMCs having a fine grain microstructure and process for forming such composites. Preferably, the boron carbide particulates are maintained in sub-micron size in the CMC. Also, desirably, the growth of SiC crystals (grains) in the CMC above 10 microns is prevented, most preferably the growth of SiC crystals above 5 microns is prevented. The term micron as used herein is synonymous with the term micrometer.

Boron carbide based ceramic matrix composites