An apparatus for interconnection in a helicopter tail rotor control linkage for changing the pitch of the tail rotor blades in response to predetermined inputs is provided. The apparatus comprises a linkage member having a variable geometry, an actuator, and a control unit. In a preferred embodiment, the control unit utilizes a microcontroller to monitor inputs corresponding to ambient air condition and automatically vary the maximum tail rotor pitch so as to provide maximum tail rotor authority over a range of altitudes.

A common configuration for a helicopter includes a first rotor, often called the main rotor or the lift rotor, rotating in a generally horizontal plane above the helicopter airframe and a second rotor, often called the tail rotor or anti-torque rotor, mounted on a tail boom and rotating in a generally vertical plane oriented to produce a sideways thrust in the direction of yaw. The pitch of the tail rotor blades, i.e., the angle between the chord line of the blade profile and the direction of rotation of the tail rotor, can be varied so as to increase or decrease the amount of sideways thrust produced by the tail rotor. The sideways thrust of the tail rotor serves three related purposes: first, since the tail rotor is located on a tail boom a distance from the main rotor, its sideways thrust produces a moment which serves to offset the torque produced on the airframe of the helicopter by the rotation of the main rotor blade; second, the sideways thrust of the tail rotor provides yaw axis control for the helicopter; and third, the sideways thrust of the tail rotor may work in conjunction with sideways thrust of the main rotor when the helicopter is translating laterally through the air.
The total sideways thrust produced by the tail rotor is known as the tail rotor authority. Factors affecting the total authority produced by a tail rotor include blade size and profile, rotational speed, angle of attack of the tail rotor blades, the pitch of the tail rotor blades, and the air density. The angle of attack is the angle between the chord line of the blade profile and the "relative wind", i.e., the direction at which the air approaches the tail rotor blade. This angle of attack is affected by the rotor blade pitch, the direction of travel of the helicopter and the presence of cross winds. A cross wind which reduces the angle of attack reduces the overall authority produced by the tail rotor, diminishing the control available to the pilot. The pitch is the angle between the chord line of the blade profile and the direction of blade rotation. The pitch is not affected by cross winds. The pilot controls the pitch of the tail rotor blades through the use of control pedals. Increasing the blade pitch results in greater tail rotor authority and decreasing the blade pitch results in less tail rotor authority. Air density also affects the tail rotor authority. Other factors being equal, the greater the air density, the greater the authority produced by the tail rotor, and similarly, the lower the air density, the less authority produced by the tail rotor. Since air density is difficult to measure directly, it is often calculated using equations based on the "standard atmosphere." The U.S. Standard Atmosphere is described in MARK's STANDARD HANDBOOK FOR MECHANICAL ENGINEERS, p. 11-67 (E. A. Avallone et al. eds., 9th ed. 1978), and Table 1 is excerpted therefrom. The U.S. Standard Atmosphere of Table 1 is a revised U.S. Standard Atmosphere, adapted by the United States Committee on Extension to the Standard Atmosphere (COESA) in 1962.
TABLE 1 ______________________________________ U.S. Standard Atmosphere Pressure Density Speed of Altitude Temp ratio, ratio sound V.sub.n h, ft* T, .degree.F..dagger. p/p.sub.o (.rho./.rho..sub.o) (.rho..sub.o /.rho.).sup.0.5 ft/s .dagger-dbl. ______________________________________ 0 59.00 1.0000 1.0000 1.000 1,116 5,000 41.17 0.8320 0.8617 1.077 1,097 10,000 23.34 0.6877 0.7385 1.164 1,077 15,000 5.51 0.5643 0.6292 1.261 1,057 20,000 -12.62 0.4595 0.5328 1.370 1,036 25,000 -30.15 0.3711 0.4481 1.494 1,015 30,000 -47.99 0.2970 0.3741 1.635 995 35,000 -65.82 0.2353 0.3099 1.796 973 36,089 -69.70 0.2234 0.2971 1.835 968 40,000 -69.70 0.1851 0.2462 2.016 968 45,000 -69.70 0.1455 0.1936 2.273 968 50,000 -69.70 0.1145 0.1522 2.563 968 55,000 -69.70 0.09001 0.1197 2.890 968 60,000 -69.70 0.07078 0.09414 3.259 968 65,000 -69.70 0.05566 0.07403 3.675 968 65,800 -69.70 0.05356 0.07123 3.747 968 70.000 -67.30 0.04380 0.05789 4.156 971 75,000 -64.55 0.03452 0.04532 4.697 974 80,000 -61.81 0.02725 0.03553 5.305 977 85,000 -59.07 0.02155 0.02790 5.986 981 90,000 -56.32 0.01707 0.02195 6.970 984 95,000 -53.58 0.01354 0.01730 7.600 988 100,000 -50.84 d.01076 0.01365 8.559 991 ______________________________________ * .times. 0.3048 = meters. .dagger. .times. (.degree.F. - 32)/1.8 = .degree.C. .dagger-dbl. .times. 0.3048 = m/s.
The values given up to about 65,000 feet are designated as standard. The region from 65,000 to 105,000 feet is designated proposed standard. The assumed sea-level conditions are: pressure, P.sub.o =29.91 inches (760 mm) of Hg=2,116.22 lb/ft.sup.2 ; mass density .rho..sub.O =0.002378 slugs/ft.sup.3 (0.001225 gm/cm.sup.3); T.sub.O =59.degree. F. (15.degree. C.). These assumed sea level conditions define what is known as a "standard day."
At this point, it is useful to define the term "density altitude" (H.sub.d). Density altitude is a convention by which air density is expressed in terms of the U.S. Standard Atmosphere altitude at which the corresponding air density is encountered. Referring to Table 1, when the actual air density outside the helicopter is 0.8617.times.sea level conditions, the density altitude, H.sub.d, equals 5,000 feet, and when the actual air density is 0.7385.times.sea level density, the density altitude, H.sub.a, equals 10,000 feet. It is important to note that as density altitude H.sub.d increases, air density is decreasing and when density altitude H.sub.d decreases, air density is increasing. Using relations developed from the Standard Atmosphere, air density expressed in terms of density altitude may be calculated using a term representing the pressure altitude H.sub.p, i.e., the altitude based on pressure values such as obtained from an altimeter, and a term using outside air temperature (OAT). In general, density altitude H.sub.d corresponds to the pressure altitude H.sub.p on a standard day, i.e., a day on which actual conditions match those of the standard atmosphere. Subsequent references to "altitude" in this description should be interpreted to mean "density altitude" unless the specific context indicates otherwise.
When operating helicopters at high altitudes, the lower air density reduces the tail rotor authority available to control the helicopter. For this reason, many helicopters have a lower cross wind rating at high altitude than they do at low altitude. By increasing the maximum pitch of the tail rotor blades, the full rated authority of the tail rotor could be restored at higher altitudes. However, the drive assembly and helicopter airframe must be designed to take the stress produced by the maximum possible tail rotor authority. Thus, a design which would allow a tail rotor pitch at high altitudes that produced full tail rotor authority would have to be strong enough to withstand the stresses imposed when the same pitch was used at a lower altitude in more dense air. If this higher blade angle was available at all altitudes, this would require, at a minimum, extensive testing and requalification of the helicopter airframe and transmission system, and possibly the use of a much heavier design if the tail rotor forces are found to be excessive for the existing structure, the overstressing the tail rotor gear box, tail boom, or overtorquing this tail rotor drive train.
Restated, the need for this invention can be summarized as follows. When a helicopter is designed for low altitude use, its subsequent use at higher altitudes will result in less control because less tail rotor authority is available in the less dense air. Because of the reduced control at higher altitudes, restrictions may be imposed on the use of the helicopter, such as load limits or cross wind limits. Alternately, where a helicopter is designed to have adequate control at higher altitudes, it will be over-designed for use at low altitudes. This over-design may result in higher costs or in increased weight, which in turn would reduce the helicopter's useful load carrying capacity. In addition, a helicopter going from low altitude service to high altitude service cannot be simply converted because the addition of a conventional tail rotor producing greater thrust will require the requalification of the helicopter by the appropriate governmental regulatory authorities, typically an expensive and time-consuming task. The current invention addresses these problems in the following ways: It allows the helicopter to maintain maximum tail rotor force at all altitudes; there is little or no weight penalty associated with the use of the current invention; it preserves the flight characteristics, i.e., the control "feel" and control pedal travel distances; it eliminates the need to requalify the airframe or tail rotor transmission when a more powerful tail rotor is provided; and it provides the pilot with useful information regarding ambient air conditions.
The present invention allows a helicopter to take advantage of increased thrust produced by larger or more powerful tail rotor blades by varying the maximum tail rotor pitch angle in relation to density altitude. The maximum tail rotor pitch will be controlled by the invention to limit the maximum tail rotor thrust produced by the new blades to be equivalent of the current production tail rotor blade's operation at sea level. This will limit the thrust generated to the previously qualified values and will therefore generate no excessive tail boom load or tail rotor drive shaft torque values. By making the maximum tail rotor thrust variable, the current invention allows the tail rotor to be compensated for loss of effectiveness due to increasing density altitude.
Since it is common for helicopters to be employed in different activities during their useful lives, it is not uncommon to find a helicopter originally acquired for low altitude work which is subsequently pressed into high altitude work. A need exists for an apparatus which controls the maximum pitch of the tail rotor blades in relation to density altitude and which can be added or retrofitted to existing helicopters as well as being incorporated into new helicopter designs.
Since the piloting of a helicopter requires great skill and experience, a helicopter pilot typically becomes accustomed to the control "feel", i.e., the control motions and forces needed to pilot the helicopter in a given situation. Many pilots would find modifications to the helicopter unacceptable which significantly changed the control "feel." Thus, a need exists for an apparatus allowing variable maximum pitch of the tail rotor blades in relation to density altitude but which maintains the same control pedal travel.
Since the torque produced by the turning of the helicopter's main rotor typically acts in the same direction, the needs for tail rotor authority are not symmetrical. For example, on a helicopter whose main rotor blades turn counterclockwise when viewed from above, the air frame of such helicopter will always be subject to clockwise torque. This clockwise torque will assist yaw motions to the right while opposing yaw motions to the left. It is frequently desirable for such a helicopter to have considerably more left tail rotor authority than right tail rotor authority. In the example of the helicopter whose main rotor blades rotate counterclockwise, increased left thrust is desired at higher altitudes, but increased right thrust is not needed. A need exists for an apparatus allowing variable maximum pitch of the tail rotor blades in one direction in relation to density altitude, while the maximum pitch of the blades in the other direction remains essentially unchanged.
The advantages of the current invention are as follows: it allows the helicopter to maintain maximum tail rotor force at all altitudes; there is little or no weight penalty associated with the use of the current invention; it preserves the flight characteristics, i.e., the control "feel" and control pedal travel distances; it eliminates the need to requalify the airframe or tail rotor transmission when a more powerful tail rotor is installed; and it provides the pilot with useful information regarding ambient air conditions.

Tail rotor authority control for a helicopter


A substantially optically transparent coated substrate product with a highly adherent, abrasion-resistant diamond-like hard carbon coating is disclosed. The substrate product is comprised of a polymeric substrate, an adhesion-mediating polysiloxane polymer layer, one or more intermediate layers and an outer layer of diamond-like hard carbon. In another embodiment of the invention a thin metallic interlayer is disposed between a first interlayer layer and subsequent interlayers and/or diamond-like hard carbon. The invention also allows for the production of adherent thin film interference layer coatings (i.e. quarter wavelength stacks and anti-reflection coatings) using diamond-like hard carbon as the high refractive index layer and the interlayer(s) as the low refractive index layer or, alternatively, using diamond-like hard carbon as the low refractive index layer and the interlayer(s) as the high refractive index layer. The invention further discloses a method for fabricating the coated substrate product. The substrate product, exhibiting excellent resistance to abrasion and chemical attack, is particularly useful for commercial plastic articles such as optical lenses and sunglass lenses made of polycarbonate, CR-39.RTM., or acrylic plastics.

The properties of polymers (i.e., plastics) make them ideal substrate materials for use in many applications. In particular, optically transparent plastics such as polycarbonate, CR-39.RTM. (allyl diglycol carbonate) and acrylics have become widely accepted materials for use as optical lenses because of their light weight and ease of molding compared to glass. Polycarbonate also has superior impact resistance compared to glass. However, a major drawback with plastic substrates, particularly polycarbonate, is their poor scratch and abrasion resistance.
Various methods have been employed to enhance the abrasion wear resistance of plastic substrates. For example, many commercial plastic opthalmic and sunglass lenses are coated with either organic acrylate-type polymer coatings or polysiloxane-type polymer coatings. (See, S. Herbert, Industrial Diamond Review, February 1984, at p.77.) Although these polymer coatings offer a significant improvement in abrasion resistance relative to the uncoated plastic lens, the perceived abrasion resistance of the coated plastic lens compared to a glass lens is still poor.
Glass and silicon dioxide have also been employed as coatings on plastic substrates to improve the abrasion resistance. Illustrative are Great Britain Patent No. 1,335,065, and U.S. Pat. Nos. 3,458,342 and 4,328,646. However, the absence of an intermediate layer between the glass or silicon dioxide layer and the plastic substrate often results in the glass or silicon dioxide coating spalling or cracking when the substrate is subjected to thermal cycling.
Several prior art techniques disclose the use of an intermediate layer between the substrate and the glass or silicon dioxide outer layer to improve adhesion of the outer layer. For example, U.S. Pat. No. 4,190,681, issued to Hall, et al., discloses an evaporative deposition technique of a glass layer disposed on top of an intermediate layer of an acrylic-type polymer which has in turn been coated onto a polycarbonate substrate. U.S. Pat. No. 4,200,681, also issued to Hall, et al., discloses the vapor deposition of a top layer of silicon dioxide onto an intermediate primer layer which in turn has been deposited on the surface of a polycarbonate substrate. However, this particular evaporative technique of applying a layer of silicon dioxide is often undesirable for several reasons. First, this technique suffers from inadequate adhesion of the silicon dioxide or glass layer, due to (i) the relatively low reactivity of the evaporated silicon oxide film-forming species, and (ii) insufficient bond strength between the silicon dioxide layer and the underlying carbonaceous acrylic polymer layer. Second, the individual particles of silicon dioxide may evaporate and later condense on the coating surface at rates which vary with the particular site of deposition, resulting in a non-uniform glass surface often characterized by pits, pinholes, and other imperfections.
U.S. Pat. No. 3,713,869, teaches the deposition of an intermediate layer polymerized by glow discharge onto a polycarbonate surface. A hard inorganic glass layer is then vaporized by an electron beam gun onto the intermediate layer in a manner similar to that used by Hall, et al. European Patent Application No. 0,266,225 further discloses a coating in which the plastic substrate is first coated with a silicon-based layer which is overcoated by a top layer of silicon dioxide. U.S. Pat. No. 4,842,941 discloses a polycarbonate substrate with an interfacial layer of resinous composition, and an abrasion-resistant top layer applied by plasma-enhanced chemical vapor deposition. U.S. Pat. No. 4,341,841 discloses an article with a multilayer protective coating, comprising a substrate and two protective layers, one being a vacuum coated ceramic layer, and one being a resinous layer, coated in any order. Although each of these prior art techniques have resulted in limited improvement in the adhesion between the glass or silicon dioxide coating and the substrate, and ultimately the wear resistance of the coated substrate product, the prior art techniques do not contemplate a diamond-like carbon ("DLC") outer layer, nor address the optimum method for obtaining an adherent DLC layer on a polycarbonate substrate.
In all of the aforementioned prior art techniques, the abrasion resistance of the coated plastic substrate has been unsatisfactory because of the limited hardness of the silicon dioxide or glass coating. Additional problems are also encountered by thin oxide coatings. Due to incomplete oxidation or inhomogeneous chemical bonding which is characteristic of oxide films, the films are susceptible to chemical reaction and damage by salt water. This is a particular disadvantage for eyeglass or sunglass lenses which are exposed to perspiration or ocean spray. Finally, under thermal cycling or flexing, the oxide coatings are susceptible to cracking and peeling.
There are also teachings of "mixed phase" or "gradient" inorganic hard coatings for plastic substrates which can be found in the prior art. For example, U.S. Pat. No. 4,830,873, issued to Benz, et al., discloses a process for applying a transparent layer onto the surface of a plastic element by first polymerizing an organic vapor and subsequently introducing additives such as oxygen, hydrocarbon compounds, or nitrogen-containing compounds to the vapor to form a layer with increased hardness. International Patent Application No. WO89/01957 discloses a method for depositing an abrasion-resistant coating comprising the plasma-enhanced chemical vapor deposition of a coating characterized by a gradual transition from a composition consisting essentially of an interfacial material to a composition consisting essentially of an abrasion-resistant material. Further, U.S. Pat. No. 4,777,090, discloses a product which has a disordered carbon coating at the substrate-coating interface and a relatively ordered portion composed of either carbon or silicon dioxide away from the substrate-coating interface. These prior art techniques similarly do not teach the deposition of a hard DLC layer, nor discuss the formation of a discrete multilayer coating structure with a polycarbonate substrate and an adherent DLC outer layer.
There are, however, several prior art references which teach the direct deposition of hard DLC films onto plastic substrates to improve abrasion resistance. Illustrative are U.S. Pat. Nos. 4,663,183, 4,770,940, 4,783,361, 4,698,256 and 4,877,677, and European Application Nos. 0,280,215 and 0,278,480. These prior art references do not teach the use of interlayer materials which have been found to be essential to achieve satisfactory adherence of the DLC film.
There are also prior art references which teach the deposition of hard DLC films onto plastic substrates with the use of limited interlayer materials. For example, U.S. Pat. No. 4,661,409, issued to Kieser, et al., discloses a substrate having an amorphous carbon coating and an adhesion-mediating interlayer of a siloxane or silazane polymer between the carbon film and the substrate. U.S. Pat. No. 4,569,738, also issued to Kieser, et al., discloses a microwave discharge process for depositing the siloxane or silazane polymer and amorphous carbon layers on the substrate. However, in each of these references only intermediate layers of microwave discharge-deposited siloxane and silazane polymers are discussed.
Although DLC coatings possess excellent optical properties and exhibit excellent resistance to abrasion and chemical attack, DLC coatings have not been widely applied to plastic substrates (including lenses) to date for several reasons. First, while DLC coatings are indeed very hard, they are also brittle when thin. Thus, when applied to soft substrates such as plastics, the DLC coating can crack and/or be crushed into the substrate when a high load or force is applied to the surface of the substrate. This mechanism is also responsible for the apparent scratching of the DLC coating from the surface of plastic substrates in severe abrasive environments.
Second, the adhesion of DLC coatings to plastic substrates has been poor due to the high internal stress associated with the DLC coatings. This poor adhesion has been especially evident during cooling of DLC coated plastic substrates from elevated temperatures. There is also a significant difference in the thermal expansion coefficients between the DLC coating and the plastic substrate. Thus, during thermal cycling the weak adhesive bonding strength at the DLC-plastic interface is overwhelmed by the forces generated by expansion and contraction, and hence, the DLC coating cracks and delaminates.
It is therefore an object of the present invention to provide a plastic substrate with hard coated surface layers, such as diamond-like carbon, firmly adhered thereto, thereby to prevent undesirable separation or crack formation, while at the same time providing excellent hardness and resistance to abrasion, chemical attack and impact.
It is a further object of the present invention to provide an abrasion-resistant plastic substrate with increased ease of cleaning.
It is a further object of the present invention to provide a plastic substrate with a diamond-like hard carbon coating which combines the ability to reflect decorative colors without sacrificing the aforementioned objects.
It is a further object of the present invention to provide a method for depositing an adherent coating incorporating high refractive index diamond-like hard carbon layers in an alternating layer stack along with at least one other material of substantially different refractive index in order to produce thin film interference coatings such as quarter wavelength stacks.
It is a further object of this invention to provide a low cost and efficient process for producing a plastic substrate with superior abrasion wear resistance and reduced chemical reactivity.

Abrasion wear resistant polymeric substrate product


An electro-optical system for high speed measuring of the dimensions of a multiplicity of articles having varying part-to-part surface reflectivity comprises impinging a modulated intensity light beam on each individual article, where the intensity of the beam impinged on the article is varied in response to the image signal from a prior beam impingement. The intensities of image signals from all articles are made comparatively uniform, to improve accuracy. Preferably, light intensity is modulated for each individual article at a speed commensurate with less than 0.004 second pass-by intervals by phase shifting a polarized laser light beam using a Pockel Cell type electro-crystallographic device. The system is particularly useful in grinding the tips of blades of gas turbine engine rotors while the blades are mounted in a spinning rotor.

One problem which the invention solves is understood with respect to one close tolerance manufacturing application: The grinding to length of the tips of gas turbine engine blades mounted in a spinning rotor. The process is generally described in Miller U.S. Pat. No. 4,512,115. The blade tips pass very quickly by both the grinding wheel contact point and the measurement point; typical times of passing are of the order of 0.004 seconds. Thus, a very quick and accurate means of measuring is required.
As described in Drinkuth et al. U.S. Pat. No. 4,501,095, a method and apparatus for accomplishing the necessary measurement comprises a laser triangulation system. Laser light is read and measurements are made for each individual blade, which measurements were not possible previously, given the high speeds at which blades pass by. A control system guides the grinding apparatus accordingly, and a uniform and precise degree of metal removal is achieved.
In process of the Drinkuth et al. patent, the light intensity impinged on the blades is controlled by a motor driven cam type mechanical aperture that blocks part of laser light emitted from the source. The intensity control seeks to make the refelected light neither too high nor too low for the position sensor. If the reflected light intensity and resultant sensor signal level is too low, the signal to noise ratio will be low and there will be resultant measurement error. On the other hand, if the reflected light intensity is too large, then the sensor will become saturated, resulting in imprecise computation of signal centroid with concomitant measurement error.
The response rate of familiar mechanical aperture devices is low, at the order of 1 Hz, compared to the 250 blade/s and greater rate at which blade tips pass by the measuring point. Thus, heretofore, the aperture has been necessarily set to provide some average light intensity for blade grinding. Such system worked satisfactorily on new rotor systems.
However, with evolving blade technology and with re-manufacturing, it has been discovered that blade tips may now vary substantially from one to the next in their surface reflectance character, compared to the general uniformity which characterized the original context of manufacturing new products. For example, some blade tips are coated; and, for a mixture of old and new blades, some will be dull and others shiny.
When using an averaged laser light intensity, for such mixtures of blades there will be erroneous measurements, defeating important objects of the original inventions. When brighter blades influence the average intensity setting, very dull blades may not be sensed; and, an absence of signal can lead to inoperability of the system, or the necessity for guessing. Analagous imprecision will occur for bright blades when the average intensity is influenced by very dull blades, for reasons given above. A not unusual maximum-minimum variation in reflected intensity is of the order of 50:1, when using an average or comprise level of intensity. And, with such a limitation, the invention is limited in being applied for other high speed measuring applications.
Thus, there has been a need for a better means of measuring blades in the prior art grinding method; and, in other measuring systems which require the essential aims of rapid accurate measurements on parts which are only momentarily available for gaging.

Optical measurement system for articles with varying surface reflectivity


In a heat exchanger such as a steam generator equipping a nuclear power station the secondary fluid is injected into the upper part of an annular space (30) formed between an outer envelope (10) and a bundle or core envelope (26) having a common vertical axis. Injection takes place by means of a supply pipe (44), which issues into an overflow or weir (62). The latter has an upper horizontal edge (64) from which the secondary fluid is discharged onto a deflecting wall (54). The secondary fluid flows along this wall towards the bottom of the annular space (30). A device (60) for trapping migrating bodies can also be placed in the overflow (62) or between the latter and the deflecting wall (54).

In heat exchangers of this type, the primary fluid generally circulates within the tubes of the bundle, whereas the secondary fluid circulates outside the tubes. More specifically, the secondary fluid is injected into the annular space formed between the outer envelope and the bundle envelope, generally into the upper part of the space, so as to drop into the aforementioned annular space and then rise again within the bundle envelope, benefitting from the heat supply provided by the primary fluid circulating in the tubes.
A known solution for injecting secondary fluid into the upper part of the annular space formed between the outer envelope and the bundle envelope is illustrated by FR-A-2 477 265. The secondary fluid penetrates the steam generator by a supply pipe, which is tightly connected to a toroidal or semi-toroidal, sealed supply collector arranged circumferentially in the top of the annular space. On its upper generatrix, the toroidal or semi-toroidal collector has holes to which are connected inverted J-shaped tubes, ensuring the injection of the secondary fluid into the annular space.
This method for injecting the secondary fluid in heat exchangers suffers from a certain number of disadvantages.
Firstly, the special shapes of the injection tubes for the secondary fluid and the upper part of the annular space in which the tubes are housed, as well as the high speed of the secondary fluid jets passing out of these tubes, lead to eddies in the upper part of the annular space. These eddies are prejudicial, because they reduce the thermal efficiency of the heat exchange, particularly when it is a preheating exchanger.
To obviate this disadvantage, FR-A-2 644 926 proposes various solutions, one of which consists of partly sealing the annular space by a non-return plate and downwardly extending the inverted J-shaped tubes by extensions passing through the non-return plate and which are fixed to the latter. However, the structure of the system making it possible to inject the secondary fluid into the heat exchanger then becomes particularly complex and costly.
Moreover, the integration of this structure into the production cycle for the heat exchangers causes problems which are difficult to solve, bearing in mind the manufacturing tolerances which lead to axial misalignments, which are variable for each inverted J-shaped tube, between the lower end of the tubes (not yet provided with their extensions) and the corresponding perforations formed in the non-return plate, in order to permit the passage of the extensions. These problems have the consequence of unduly extending the production cycle for the heat exchangers.
The fixing of the extensions to the non-return plate and to the ends of the inverted J-shaped tubes also leads to a risk of the extensions fracturing under the effect of mechanical stresses produced by differential expansions occurring between operating periods and stoppage periods of the exchanger.
In U.S. Pat. No. 3 913 531 and U.S. Pat. No. 3 906 905, the secondary water supply of a steam generator is also ensured by means of a toroidal collector placed in the top of the annular space formed between the outer envelope and the bundle envelope. On its lower generatrix, the toroidal collector has holes, which issue downwards and directly into the annular space.
Although this arrangement is particularly simple, it also leads to the formation of eddies in the top of the annular space. Moreover, stopping the secondary water supply brings about a complete emptying of the collector, so that water-hammer may occur on resuming the supply.

Heat exchanger, in which the supply of secondary fluid takes place in the upper part by means of an overflow


A circuit and method for correcting erroneous data in memory for pipelined reads. A memory controller includes a control unit, a storage unit and an error detection and correction unit. The control unit is configured to read data including an associated error correction code from a memory subsystem in response to a memory read request. The error detection and correction unit is coupled to receive the data and configured to determine whether an error exists in that data based upon the associated error correction code. The control unit is configured to store an indication in the storage unit that the data corresponding to the memory read request is erroneous. The control unit is further configured to detect the indication in the storage unit and to responsively perform a subsequent read of the data from the memory subsystem and to write a corrected version of the data back to the memory subsystem.

1. Field of the Invention
This invention relates to computer systems and, more particularly, to memory controllers that correct errors in data stored within computer system memories.
2. Description of the Related Art
A computer system may employ error correcting code (ECC) circuits which allow the system to detect and/or correct erroneous data. The ECC circuits may be used in various capacities by the system. In some systems, a memory controller may employ an ECC circuit to correct errors in data returned from the system memory. A separate ECC circuit may be used in the processor.
Many memory controllers include the ECC circuit in the data path to and from main memory. In such memory controllers, the ECC circuit may generate an error correction code for data written to memory. As read requests arrive, a memory request queue and associated command logic processes the read requests by placing the read request onto a command bus. When that data is returned from memory, the ECC circuit may use the corresponding error correction code to detect an error in the data. Many ECC circuits also correct the error on the fly and since the ECC circuit is in the data path, the corrected data may be sent to the requesting device. This method is common and may provide a relatively fast data return time, especially for pipelined reads. However, the erroneous data is left in memory.
To correct the erroneous data stored in memory, another type of memory controller may be used. In such a memory controller, a read buffer may be employed which stores the address and data returned from each read request. The ECC circuit may first correct the data and then store the corrected version in the buffer. Alternatively, the erroneous data may be stored in the buffer and corrected at a later time. In the former case, once any pending read requests are processed, the corrected data corresponding to each read request may be subsequently written back into memory into the respective memory locations. In the latter case, the erroneous data may be read out of the buffer and the ECC circuit may correct the data. The corrected data corresponding to each read request may be subsequently written back into memory into the respective memory location.
Thus in this type of memory controller, the erroneous data in memory may be replaced by a corrected version. Replacing erroneous data with a corrected version is sometimes referred to as scrubbing. However, as described above, a buffer may be used that is large enough to hold the entire data path. As data bus widths increase, the size of such a buffer may become necessarily large. In addition, other factors such as latencies associated with the data arrival and read wait states may also necessitate a large buffer. A corresponding increase in the area required to manufacture the die may also be necessary. Since there is a direct relationship between die area and manufacturing costs, it may be desirable to have a memory controller that provides memory data scrubbing without the use of a buffer which stores the data returned from a read request.

Circuit and method for correcting erroneous data in memory for pipelined reads


An electric-vehicle air-conditioning apparatus small in size, simple in construction and high in reliability, which can be used for many types of vehicles, includes a battery, a conducting device connected in series with the battery, a switching device connected in parallel to the conducting device, a capacitor charged from the battery through the conducting device, a device supplied with power from the battery through the switching device for driving an electrically-operated air-conditioning compressor. The conducting device is adapted to charge the capacitor with a constant current.

1. Field of the Invention
The present invention relates to an air-conditioning apparatus for the electric vehicle having a compressor driven by the electric power supplied from a battery.
2. Description of the Related Art
In an air-conditioning apparatus for the electric vehicle, the device for driving an electrically-operated compressor for air-conditioning purposes supplies a large current to the electrically-operated compressor. Therefore, the large electric noise interferes with the car radio, and the large current fluctuations adversely affects the durability of the battery for supplying the current. As a result, it is necessary, as shown in the current waveform diagrams of FIG. 5(a) and (b), to smooth the current supplied to the electrically-driven compressor thereby to suppress the electric noise and current fluctuations. For this purpose, a capacitor of large electrostatic capacity is provided at a point where the electrically-operated compressor driving means is supplied with electric power through a switching device from the battery.
The provision of a capacitor with a large electrostatic capacity, however, causes a large charge current to flow to the capacitor on the instant the battery is connected. The resulting problem is that the fuse blows out or the pattern wiring of the printed board is broken, or a surge current is generated by the resonance with the inductance component of the wiring from the battery as shown by the waveform diagram of FIG. 5(c), thereby damaging the electrically-operated compressor driving means.
In order to suppress the charging surge current to the capacitor on the instant the battery is connected, the capacitor is charged through a conducting device. Normally, a resistor is used as the conducting device.
The operation of a conventional air-conditioning apparatus for the electric vehicle will be explained with reference to the circuit diagram of FIG. 7 showing a conventional air-conditioning apparatus for the electric vehicle and the circuit operation diagram for the air-conditioning apparatus for the electric vehicle shown in FIG. 8. With the battery 2 connected, the voltage Vc of the capacitor 11, the current Ir of the resistor 8 and the current Ic of the capacitor 11 are determined as shown in FIG. 8 from the time constant based on the resistance value of the resistor 8 and the electrostatic capacity of the capacitor 11. When the capacitor 11 is charged and input voltage detector means 7 detects a voltage of more than a predetermined value, a controller 6 closes the switching device 3, and power is supplied through the switching device 3 from the battery, thereby causing the electrically-operated compressor driving device to drive the electrically-operated air-conditioning compressor.
The resistance value of the resistor 8 is required to be sufficiently large to suppress the charging surge current as described above. On the other hand, the resistance value of the resistor 8 must be small enough to blow out the fuse at the time of a malfunction such as the damage to the electrically-operated compressor driving device or the shortening of the capacitor. The value of the fuse is about 10 A to blow out positively at the time of a malfunction. The resistance value of the resistor 8 becomes 7.5 ohm if the voltage across the battery 2 is 300 V to assure current flow of 40 A to blow out the fuse positively at the time of a malfunction. When the battery 2 is connected, therefore, the current of about 40 A flows, the subsequent current being determined by the time constant. The larger the electrostatic capacity of the capacitor 11, the larger the time constant, thereby increasing the power consumption of the resistor 8 accordingly. The electrostatic capacity of the capacitor 11 normally assumes a large value of about 1000 .mu.F for smoothing the current. At the time of connecting the battery 2, the instantaneous maximum power consumption of the resistor 8 is 300 V.times.40 A=12,000 W. A large-power resistor 8 must therefore be used to maintain the reliability thereof. According to the guaranteed specification of the resistor 8, the resistor 8 is a rated product of about 60 W.
As seen from FIGS. 6A and 6B showing the form of the resistor, a large space is required for the controller of the vehicle air-conditioning apparatus even when two 30 W resistors instead of a 60 W resistor are used.
In the case where the electrically-operated compressor driving device or capacitor is in a minor trouble such as when the current of 9 A flows with the fuse not blown out, the resistor 8 consumes large electric power of (9 A)2.times.7.5 ohm=607.5 W, thereby compromising the reliability due to the smoking, solder melting or wiring damage due to overheating.
In the case where a resistor is used as a conducting device as described above, such a resistor must be a large-power item of about 60 W. The large-power resistor, due to the large size, can not be directly connected on the printed circuit board in the electrically-operated compressor driving device, and requires a considerable space to be secured for mounting, thereby leading to a bulky air-conditioning apparatus. The air-conditioning apparatus for the electric vehicle must be installed in a limited space in the vehicle, and therefore must be as small as possible. A conducting device is required which does not cause an increased size of the air-conditioning apparatus.
In the case where a resistor is used as a conducting device, a wiring is required of the resistor, and further the wiring must be fixed in order not to be damaged by contact with a heat generating material or a metal edge. The resulting complicated and bulky structure of a conducting device makes fabrication difficult.
Also, the resistance value of the resistor is required to be sufficiently large to suppress the charging surge current. On the other hand, the resistance value must be small enough to allow the fuse to blow out when the electrically-operated compressor driving device is damaged or the capacitor is shorted. The resistance value of the resistor, therefore, must be changed in accordance with the battery voltage or the electrostatic capacity of the capacitor. Since the battery voltage of the electric vehicle is so varied and the capacity required of the air-conditioning apparatus varies from one vehicle to another, different amounts of current are supplied to different electrically-operated compressors. It is therefore necessary to change the resistance value of the resistor for different air-conditioning apparatuses or vehicles, with the result that an increased number of types of air-conditioning apparatus complicates the production control, often raising the problem of an increased cost or other production-related problems.
Also, when the electrically-operated compressor driving device or the capacitor is in minor trouble with the fuse not blown out, the resistor consumes large electric power for a reduced reliability due to overheat. As a result, the measure taken for heat radiation undesirably increases the size of the air-conditioning apparatus.
Further, the capacitor, when connected in reverse polarities, is "punctured" to damage the apparatus. When a switching power supply is connected in parallel to the capacitor, a sharp voltage increase may damage the switching power circuit.

Air-conditioning apparatus for electric vehicle

Matsushita Electric Industrial Co., Ltd.


Disclosed in one general aspect is a particle interaction characterization instrument that comprises a flow cell for a liquid sample that includes suspended particles and a light source positioned to illuminate the suspended particles in the liquid sample fluid in the sample vessel. A first scattering detector is positioned to receive light from the light source that has been scattered by the particles suspended in sample fluid in the sample vessel at at least one predetermined scattering angle. An ultraviolet transmittance detector is positioned to receive a portion of the light from the source that passes through the suspended particles without being absorbed or scattered. Interaction analysis logic is responsive to both the scattering detector and the ultraviolet detector, and is operative to derive at least one interaction property for the suspended particles.

Measuring molecular self-interaction can help to indicate whether particular particles will aggregate or crystallize. One measure of self-interaction is the B22 interaction parameter. Prior art methods of detecting the B22 interaction parameter are described in U.S. Pat. No. 7,630,076 and US Appl. No. 20070291265, which are herein incorporated by reference. As shown in FIG. 1, these methods involve performing scattering and ultraviolet (UV) absorbance measurements on a sample in a flow cell.

Particle interaction characterization using overlapping scattering and concentration measurements


A docking station for a patient monitoring device and method of locking the patient monitoring device in the docking station is provided. A housing selectively supports a patient monitoring device thereon and a first port positioned on the housing receives a patient monitoring device therein. A sensor senses one of a presence and absence of the patient monitoring device within the first port. A locking mechanism mechanically locks the patient monitoring device within the first port, wherein the locking mechanism maintains the docking station and patient monitoring device in a mechanically locked state in response to sensing the presence of the patient monitoring device within the first port.

During the course of providing healthcare to patients, practitioners typically connect at least one type of sensor to a patient to sense, derive and otherwise monitor at least one type of patient medical parameter. These patient connected sensors are further connected to a monitoring device that includes all relevant electronic components that enable conversion, manipulation and processing of the data sensed by the at least one type of sensor in order to generate the patient medical parameter. These patient medical parameters are usable by healthcare practitioners (e.g. nurses, doctors, physician assistants, or any other person charged with providing a healthcare service to a patient) in monitoring a patient and determining a course of healthcare to be provided to the patient.
Patient monitoring devices may be selectively connected to the patients at any point during which a healthcare professional comes into contact with the patient and thus may remain connected with the patient as the patient moves through various locations within a particular healthcare enterprise (e.g. hospital) or between different healthcare enterprises (e.g. different medical facilities). Once it is determined that a patient is to remain in a fixed location, the patient monitoring devices are selectively connected (docked) to a docking station that may serve as a gateway for connecting the patient monitoring device to a hospital information system (HIS) and/or central monitoring station and allowing data representing the at least one patient medical parameter to be communicated to other systems within the healthcare enterprise. This data may then be used by different systems in further patient care.
Once docked it is imperative to ensure that the patient monitoring device remains securely connected to the docking station. Secure connection of the patient monitor with the docking station protects against inadvertent displacement or disconnection thereof resulting in injury to a patient or healthcare professional or damage to the monitor. Further, the secure connection of the patient monitoring device with the docking station maintains an electronic connection between the docking station and the various other information systems. However, it is also necessary for the patient monitoring device to be removed to allow the patient to move between various care units. A drawback associated with the locking and removal of conventional patient monitoring devices is requiring two handed operation to complete both actions. This may result in delaying the movement of the patient which may negatively impact the health of the patient. A further drawback associated with the locking and removal of convention patient monitoring devices using a two-handed release is that the healthcare professional is prevented from using the second hand for other duties because it is needed to remove and disconnect the monitoring device from the docking station. An apparatus and method of operating the apparatus according to invention principles addresses deficiencies of known docking station locking mechanisms.

Electronic locking mechanism for a docking station


A bottom hole assembly for performing a borehole treatment has a plurality of ported valve housings where the housings have an assembly of shifting sleeves. The first sleeve is shifted uphole to open the port in the housing and lock the first sleeve in the ports open position. A second sleeve in the same housing is shifted in the same direction as the first sleeve to close the ports in the housing. The second sleeve has profiles for shifting it up to close the housing ports and back down to reopen the housing ports after closing them.

In the past frack or other treatment valves operated with a single sleeve that had to be moved in opposed directions to open and close the ports. In some deviated boreholes enough force to shift a sleeve in the downhole direction with set down weight is not available. Sliding sleeve valves were used in pairs or did not have the capacity to be reopened after closing or had other limitations making them unsuitable for treatment is certain applications. The following references are illustrative of some known designs of sliding sleeve valves for borehole treatment operations: U.S. Pat. Nos. 7,591,312; 8,127,847 and US 2009/0139717.
The present invention addresses the issues of the prior designs of sliding sleeve valves for treatment applications in a borehole by providing a tandem sleeve design where the sleeves are pulled uphole. The first sleeve movement opens housing ports and movement of a second sleeve in the same direction moves the second sleeve to where the first sleeve started for the closed position of the ports in the valve housing. The closing sleeve can also be functioned back down in the event the ports in the valve housing need to be reopened. The opening sleeve can be locked in the open position after it is shifted. Known spears using selectively supported collets can be used to shift the opening sleeve and a linkage type shifting tool such as an HB-3 shifting tool from Baker Hughes Incorporated can be used to shift the closing sleeve to close the housing ports. Two HB-3 shifters oriented in mirror image can be used to move the closing sleeve up for closing the housing ports with one shifter and to move the closing sleeve back down to reopen the housing ports.
Those skilled in the art will have a better understanding of the present invention from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.


A thin film deposition system includes a vacuum or evacuated casing in which there is introduced an active gas or an inert gas or a mixture thereof. A filament emits thermions which impinge upon gas molecules to ionize them into positive ions. The ions bombard a target, from which particles are emitted toward a substrate. The particles emitted from the target are also ionized by the thermions. In the vicinity of a grid, more particles from the target are ionized by thermions which are vertically oscillated and ionized molecules of the gas. The ions are accelerated toward the substrate and bombard the substrate, thereby depositing a thin film thereon. The thin film deposition system may additionally have an evaporation source for supporting an evaporant which emit particles to be deposited on the substrate.

1. Field of the Invention
The present invention relates to a thin film deposition system for depositing thin films while simultaneously utilizing the strong reaction of the chemical vapor deposition (CVD) process and the film growth in a high vacuum of the physical vapor deposition (PVD) process, and also for easily depositing compound thin films.
2. Prior Art
Among well known thin film deposition systems for depositing thin films on substrates are CVD and PVD systems. The CVD systems provide a strong reactive process, whereas the PVD systems can deposit dense, strong thin films in a high vacuum.
There have been proposed various thin film deposition systems and processes based on the CVD and PVD principles. However, these conventional thin film deposition systems have been disadvantageous in that a substrate and a thin film deposited thereon are not intimately joined together, it is difficult to deposit a thin film on a substrate which is not resistant to heat, and desired compound thin films cannot easily be deposited.
Various efforts have been made to solve the above problems. One attempt is directed to a thin film deposition system known as an ion plating system. In the ion plating system, a high-frequency electromagnetic field is generated between an evaporation source supporting an evaporant and an object on which a thin film is to be deposited, thereby ionizing the evaporant which is evaporated in an active gas or an inert gas and depositing the ionized evaporant as a thin film on the object in a vacuum. According to another proposal, a DC voltage is applied between an evaporation source and an object on which a thin film is to be deposited in a thin film deposition system known as a DC ion plating system. For further details, reference should be made to Japanese Patent Publications Nos. 52(1977)-29971 and 52(1977)-29091, for example.
Still another thin film deposition system which has been proposed to eliminate the drawbacks is disclosed in Japanese Laid-Open Patent Publication No. 59(1984)-89763. In the disclosed system, a substrate is held on an electrode confronting an evaporation source, a grid is disposed between the confronting electrode and the evaporation source, and a filament for emitting thermions is disposed between the grid and the evaporation source. The grid is held at a positive potential with respect to the filament while a thin film is being deposited on the substrate.
More specifically, the material which has been evaporated from the evaporation source is ionized by thermions emitted from the filament, and the ionized material is accelerated by an electric field directed from the grid toward the confronting electrode when the ionized material passes through the grid. The accelerated ionized material impinges upon the substrate, whereupon a thin film is deposited on the substrate in intimate adhesion thereto.
When a multiple-element thin film such as an ITO film whose properties are greatly variable by a small doped amount of a certain element is to be deposited, it is difficult for the conventional thin film deposition systems to effectively introduce such a small amount of an element into the film.


A recreational vehicle for transporting at least two riders comprising (i) a propulsion device adapted for use by a first rider and having a brake and (ii) a go-cart adapted for use by a second rider and having steering device attached thereto, whereby the first rider provides propulsion and braking for the vehicle and the second rider provides steering for the vehicle. In a preferred embodiment, the propulsion device is the rear portion of a conventional bicycle. The go-cart has front and rear compartments, with the front compartment adapted for use by a forward facing rider and the rear compartment adapted for use by a rearward facing rider.

In the past, vehicles such as wheel chairs and baby carriages have been joined to the rear portion of a bicycle-like device so that the vehicle could be powered by the rider of the bicycle-like portion--see, for example, U.S. Pat. Nos. 4,830,388 (Wang); 4,770,431 (Kulik); 2,482,585 (Hauptman) and 1,661,257 (Kirch). Such approaches suffer from two disadvantages if applied to provide temporary power for a child's go-cart. First, extensive modification of the bicycle is often required to couple it to the other vehicle. This makes it unsuitable to satisfy the more or less spontaneous desire on the part of an adult and child to power the child's go-cart using the adult's bike on a given day while, allowing both devices to be converted back to independent use on short notice--that is, it is unlikely that the adult will undertake the effort required to couple his/her bicycle to the child's go-cart to "go for a ride" if substantial effort is required to couple the bicycle to the go-cart before the ride and then additional substantial effort is required immediately thereafter so that the bicycle and go-cart remain available for independent use.
The second disadvantage associated with the approaches disclosed in the aforementioned patents, when applied to recreational use with a go-cart, is that the passenger in the vehicle has a passive role since the rider of the bicycle provides both the power and the steering for the vehicle. While this approach may be desireable, or even necessary, with respect to the handicapped and infant occupants of the wheel chairs and baby carriages of the prior art vehicles, it is unsuitable for use in go-carts with active young child who are easily bored with passivity.
Consequently, it would be desirable to provide a recreational vehicle that could be easily formed by temporarily integrating a conventional bicycle with a go-cart and that allowed the occupant of the go-cart to take an active role in operating the vehicle.


An inside blowout preventer well tool includes an elongated body threaded at both ends and including an axial opening. A flapper is pivotally mounted on a side of the opening and movable between a lower-open position and an upper-closed position. A downwardly-facing valve seat is formed around the opening, the flapper engaging the seat in the upper-closed position. A spring urges the flapper toward the seat and a piston is movable in the opening between an upper position, where the lower end of the piston is above the valve seat, and a lower position, where the piston encases the flapper and holds it in the lower-open position. The piston is normally urged toward its upper position, the piston being shaped so that when the internal pressure of drilling mud normally circulating through the opening is greater by a predetermined amount than pressure outside the body, the pressure differential will overcome the force urging the piston upwardly and move the piston to the lower position. The piston is also responsive to fluid pressure outside the body so that the piston will automatically be moved to its upper position when the pressure differential is reduced by a predetermined amount.

U.S. Pat. No. 3,861,470 and other related U.S. patents cited therein, all of which are owned by the same corporate entity which owns the subject invention, are directed to a blowout preventer method and apparatus which utilize a ball-shaped valve that opens and closes automatically in response to changes in pressure differential between the wellbore and the annulus between the drill string and the wall of the drill hole. When the pressure differential is lost a ball element is automatically rotated shut. After conditions return to normal a spring or other pressure exerting means operates to rotate the ball valve back to its open position.
Although this blowout preventor valve proved effective for its intended purpose, it has the disadvantage that well tools cannot be run below the valve when the ball is closed.
Further, with ball valves of the types described above the internal components inherently have a relatively small bore in the valve which causes a pressure drop across the valve and requires a higher pump pressure for effective operation.


A method for increasing the efficiency of generating lasers by pumping two separate wavelengths into an erbium-based medium to populate the 4I11/2 state and depopulate the 4I13/2 state. A first excitation wavelength region is located between approximately 955 nm to approximately 1100 nm. The second excitation wavelength region is located between approximately 1600 nm to approximately 1850 nm. This multi-wavelength pumping scheme may be operated in continuous wave or quasi-continuous wave mode.

For certain applications, it is desirable to use mid-infrared lasers that directly emit radiation between wavelengths in the 2-5 micron region operating at pulse repetition frequency (PRF) ranging between 1 Hz-100 kHz or in continuous wave, and which can also be scalable in terms of their output power. Erbium-based (Er-based) lasers, operating on the 4I11/2→4I13/2 transition, have been shown to emit radiation between approximately 2.6 to approximately 3 microns. The terminal lasing state in the above-mentioned Er-based lasers self-terminates due to long fluorescent lifetime of the 4I13/2 lower lasing state (˜2.5-7.5 msec) relative to the 4I11/2 upper lasing state (˜0.09-1.5 msec). To a first order approximation, the highest pulse repetition frequency that can be achieved in these lasers is inversely proportional to the fluorescent lifetime of the lower lasing state (in this case, the 4I13/2 state). In the case of the nominally 50% doped Er:YAG laser medium which emit radiation at approximately 3 microns wavelength, the 2.5-7.5 msec fluorescent lifetime of the 4I13/2 state implies that the highest PRF operation is still less than 1 kHz. In order to achieve operation at PRF greater than few 100 Hz, the effective fluorescent lifetime of the 4I13/2 state in Er must be reduced to a value approximately equal to the reciprocal of the desired PRF value and/or the population of the 4I13/2 state must be significantly reduced to or below that of the population of the 4I11/2 state so as to minimize or eliminate the above-mentioned self-termination process. It has been well documented in published literature that the effective fluorescent lifetime of the 4I13/2 state in Er decreases with increasing Er doping concentration.
In addition, the approximately 3 micron lasing action (especially the continuous wave mode of operation) which occurs as a result of the 4I11/2→4I13/2 transition in Er, is highly dependent on the upconversion process as this energy transfer mechanism assists in alleviating the self-termination process (see FIG. 1). Two competing upconversion processes take place in Er. In one process, two Er ions in the 4I13/2 state interact such that one of the two Er ions is de-excited to the 4I15/2 ground state while the second Er ion is energized to the 4I9/2 state which via a fast non-radiative process decays to the 4I11/2 upper lasing state thus enhancing the population inversion between the upper and lower lasing states and the overall quantum efficiency of the lasing action. The energy given off by the Er ion decaying from the 4I13/2 state to the 4I15/2 ground state is identical to the energy gained by the Er ion in transitioning from the 4I13/2 state to the 4I9/2 state. The second upconversion process, involving two Er ions in the 4I11/2 upper lasing state, results in exciting one Er ion to the 4F7/2 state, while relaxing the second Er ion to the 4I15/2 ground state. The former upconversion process is beneficial in that it removes two Er ions from the 4I13/2 lower lasing state thereby assisting in the enhancement of the population inversion by depopulating of the 4I13/2 lower lasing state. The latter upconversion process, while not preventing the generation of the ˜3 micron radiation, is undesirable in that it takes two Er ions out of the 4I11/2 upper lasing state thereby decreasing the net population inversion and thus negatively impacting the overall efficiency of the laser operation.
Much of the prior art, which aims to improve the lasing efficiency or enhance the PRF in Er-based lasers emitting at approximately 3 micron does so by attempting to promote the (beneficial) upconversion process involving two Er ions in the 4I13/2 state and/or depopulating the 4I13/2 state by codoping with certain other rare earth ions.

Multi-wavelength pump method for improving performance of erbium-based lasers


Exemplary embodiments provide a packing leak detection system for leaks or discharge of a volatile material which discharge into the environment is subject to regulation. The system contains a compressor apparatus including a compressor cylinder, a compressor piston, a compressor piston rod positioned in a packing case, wherein a volatile material being compressed by the compressor apparatus leaks from the packing case. Also provided is a leak detector sized and configured to detect and monitor leaks of the volatile material from the packing case. Methods of assessing leaks of a volatile material subject to environmental regulation are also provided.

I. Field
The present invention relates to a system for monitoring and annunciating leakage of gas vapors and/or volatile material from a volatile material compressor.
II. Background
A volatile material (gas) compressor is a pressure vessel in which a piston, moved by a compressor piston rod, compresses a volume of volatile material by decreasing the space in which the volatile material is contained. As the pressure increases, the higher pressure volatile material attempts to escape along the surface of the compressor piston rod and out of the compressor cylinder through the opening for the compressor piston rod. Packing material, which may take the form of a series of special rings, contained in a packing case, surrounds the compressor piston rod and impedes the volatile material from escaping into the environment.
When the packing material comprises rings, the efficiency of the rings is determined by several factors which include the conditions of the compressor piston, the compressor piston rod, the packing case and the rings, themselves. Wear of the packing rings is expected, and the timing of their replacement is crucial to efficient operation of the compressor apparatus and other compressor equipment.
We observe that regulatory requirements in the area of pollution prevention are becoming more and more stringent. Depending on the particular volatile material being compressed, for example, a volatile material (VOC) which may be regulated by the Environmental Protection Agency (EPA), leaks of escaping VOCs from a compressor apparatus can represent significant loss of revenue and could trigger possible environmental fines for the compressor operator.
Similarly, national emission standards for hazardous air pollutants (NESHAP) established pursuant to Section 112 of the Clean Air Act (as amended Nov. 15, 1990) regulate specific categories of stationary sources that emit (or have the potential to emit) one or more hazardous air pollutants (HAPs) (see generally Title 40 of the Code of Federal Regulations). Some examples of HAPs include formaldehyde, benzene, 1,3-butadiene, acrolein, acetaldehyde, and toluene (see larger illustrative list in Table 1). Similarly, a set of pollutants commonly referred to as "Criteria Pollutants" face regulatory scrutiny. These pollutants are generated by combustion and include Nitrous Oxides (NOx), Carbon Monoxide (CO) and Volatile Organic Compounds (VOCs). These compounds are regulated by the New Source Performance Standards (NSPS). A third set of regulated (or potentially soon-to-be regulated) gases are greenhouse gases (GHG), for example, methane and carbon dioxide.
TABLE 1Illustrative List of Hazardous Air Pollutants.CASChemicalNumberName75070Acetaldehyde60355Acetamide75058Acetonitrile98862Acetophenone539632-Acetylaminofluorene107028Acrolein79061Acrylamide79107Acrylic acid107131Acrylonitrile107051Allyl chloride926714-Aminobiphenyl62533Aniline90040o-Anisidine1332214 Asbestos71432Benzene (including benzene from gasoline)92875Benzidine98077Benzotrichloride100447Benzyl chloride92524Biphenyl117817Bis(2-ethylhexyl)phthalate (DEHP)542881Bis(chloromethyl)ether75252Bromoform1069901,3-Butadiene156627Calcium cyanamide105602Caprolactam133062Captan63252Carbaryl75150Carbon disulfide56235Carbon tetrachloride463581Carbonyl sulfide120809Catechol133904Chloramben57749Chlordane7782505Chlorine79118Chloroacetic acid5322742-Chloroacetophenone108907Chlorobenzene510156Chlorobenzilate67663Chloroform107302Chloromethyl methyl ether126998Chloroprene1319773Cresols/Cresylic acid (isomers and mixture)95487o-Cresol108394m-Cresol106445p-Cresol98828Cumene947572,4-D, salts and esters3547044DDE334883Diazomethane132649Dibenzofurans961281,2-Dibromo-3-chloropropane84742Dibutylphthalate1064671,4-Dichlorobenzene(p)919413,3-Dichlorobenzidene111444Dichloroethyl ether (Bis(2-chloroethyl)ether)5427561,3-Dichloropropene62737Dichlorvos111422Diethanolamine121697N,N-Dimethylaniline64675Diethyl sulfate1199043,3-Dimethoxybenzidine60117Dimethyl aminoazobenzene1199373,3′-Dimethyl benzidine79447Dimethyl carbamoyl chloride68122Dimethyl formamide571471,1-Dimethyl hydrazine131113Dimethyl phthalate77781Dimethyl sulfate5345214,6-Dinitro-o-cresol, and salts512852,4-Dinitrophenol1211422,4-Dinitrotoluene1239111,4-Dioxane (1,4-Diethyleneoxide)1226671,2-Diphenylhydrazine106898Epichlorohydrin (1-Chloro-2,3-epoxypropane)1068871,2-Epoxybutane140885Ethyl acrylate100414Ethyl benzene51796Ethyl carbamate (Urethane)75003Ethyl chloride (Chloroethane)106934Ethylene dibromide (Dibromoethane)107062Ethylene dichloride (1,2-Dichloroethane)107211Ethylene glycol151564Ethylene imine (Aziridine)75218Ethylene oxide96457Ethylene thiourea75343Ethylidene dichloride (1,1-Dichloroethane)50000Formaldehyde76448Heptachlor118741Hexachlorobenzene87683Hexachlorobutadiene77474Hexachlorocyclopentadiene67721Hexachloroethane822060Hexamethylene-1,6-diisocyanate680319Hexamethylphosphoramide110543Hexane302012Hydrazine7647010Hydrochloric acid7664393Hydrogen fluoride (Hydrofluoric acid)7783064Hydrogen sulfide123319Hydroquinone78591Isophorone58899Lindane (all isomers)108316Maleic anhydride67561Methanol72435Methoxychlor74839Methyl bromide (Bromomethane)74873Methyl chloride (Chloromethane)71556Methyl chloroform (1,1,1-Trichloroethane)78933Methyl ethyl ketone (2-Butanone)60344Methyl hydrazine74884Methyl iodide (Iodomethane)108101Methyl isobutyl ketone (Hexone)624839Methyl isocyanate80626Methyl methacrylate1634044 Methyl tert butyl ether1011444,4-Methylene bis (2-chloroaniline)75092Methylene chloride (Dichloromethane)101688Methylene diphenyl diisocyanate (MDI)1017794,4′-Methylenedianiline91203Naphthalene98953Nitrobenzene929334-Nitrobiphenyl1000274-Nitrophenol794692-Nitropropane684935N-Nitroso-N-methylurea62759N-Nitrosodimethylamine59892N-Nitrosomorpholine56382Parathion82688Pentachloronitrobenzene (Quintobenzene)87865Pentachlorophenol108952Phenol106503p-Phenylenediamine75445Phosgene7803512Phosphine7723140Phosphorus85449Phthalic anhydride1336363Polychlorinated biphenyls (Aroclors)11207141,3-Propane sultone57578beta-Propiolactone123386Propionaldehyde114261Propoxur (Baygon)78875Propylene dichloride (1,2-Dichloropropane)75569Propylene oxide755581,2-Propylenimine (2-Methyl aziridine)91225Quinoline106514Quinone100425Styrene96093Styrene oxide17460162,3,7,8-Tetrachlorodibenzo-p-dioxin793451,1,2,2-Tetrachloroethane127184Tetrachloroethylene (Perchloroethylene)7550450Titanium tetrachloride108883Toluene958072,4-Toluene diamine5848492,4-Toluene diisocyanate95534o-Toluidine8001352Toxaphene (chlorinated camphene)1208211,2,4-Trichlorobenzene790051,1,2-Trichloroethane79016Trichloroethylene959542,4,5-Trichlorophenol880622,4,6-Trichlorophenol121448Triethylamine1582098 Trifluralin5408412,2,4-Trimethylpentane108054Vinyl acetate593602Vinyl bromide75014Vinyl chloride75354Vinylidene chloride (1,1-Dichloroethylene)1330207Xylenes (isomers and mixture)95476o-Xylenes108383m-Xylenes106423p-Xylenes0Antimony Compounds0Arsenic Compounds (inorganic including arsine)0Beryllium Compounds0Cadmium Compounds0Chromium Compounds0Cobalt Compounds0Coke Oven Emissions0Cyanide Compounds10Glycol ethers20Lead Compounds0Manganese Compounds0Mercury Compounds0Fine mineral fibers30Nickel Compounds0Polycylic Organic Matter40Radionuclides (including radon)50Selenium CompoundsNOTE:For all listings above which contain the word "compounds" and for glycol ethers, the following applies: Unless otherwise specified, these listings are defined as including any unique chemical substance that contains the named chemical (i.e., antimony, arsenic, etc.) as part of that chemical's infrastructure.1X′CN where X = H′ or any other group where a formal dissociation may occur. For example KCN or Ca(CN)22Includes mono- and di- ethers of ethylene glycol, diethylene glycol, and triethylene glycol R—(OCH2CH2)n—OR′ where: n = 1, 2, or 3 R = alkyl or aryl groups R′ = R, H, or groups which, when removed, yield glycol ethers with the structure: R—(OCH2CH)n—OH. Polymers are excluded from the glycol category.3Includes mineral fiber emissions from facilities manufacturing or processing glass, rock, or slag fibers (or other mineral derived fibers) of average diameter 1 micrometer or less.4Includes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100° C.5A type of atom which spontaneously undergoes radioactive decay.
A business that fails to monitor and take appropriate action to correct leaks of volatile organic compounds (VOCs), hazardous air pollutants (HAPs), Criteria Pollutants or greenhouse gases (GHGs) is taking a risk of having their operating permits suspended in addition to the possibility of incurring significant fines. As used herein, the term "volatile material" includes, without limitation, VOCs, HAPs, Criteria Pollutants and GHGs.
In addition to regulatory concerns, we speculate that the lost revenue of escaping VOCs and other volatile materials at the site of compression of these gases is a significant incentive to monitor compressor equipment to enable quick repair or replacement of compressor equipment in the event of detected volatile material leaks.
Currently within the industry, we have sometimes observed that the decision by the compressor operator regarding the timing of maintenance is left to either audible detection of volatile material leaks or physical detection of escaping gas by placement of the operator's hand on the compressor apparatus (to detect the stream of the escaping volatile material). Thus, there is a continuing need for a system that can reliably monitor and annunciate emissions of equipment, such as compressors of volatile materials such as VOCs.


A wafer is supplied from a wafer cassette to an etching part by a wafer transport robot so as to be etched. After the etching process, a wafer frame is supplied from a wafer frame supply part to a mount part. The mount part to which the wafer frame is supplied moves to the upper part of a processing vessel of the etching part, and mounts the wafer at that position. After that, the mount part returns to its original position. A wafer frame collecting robot collects the wafer frame from the mount part that has returned to its original position, and stores the wafer frame in the wafer frame cassette.

1. Field of the Invention
The present invention relates to an etching apparatus, more particularly to an etching apparatus which etches a wafer, of which reverse has been ground by a planarization apparatus, and then automatically mounts the wafer on a wafer frame for dicing.
2. Description of Related Art
Demands have been increasing to make thinner semiconductor elements because of the needs of the elements for IC cards. Then, after predetermined circuit patterns are formed on the obverse of a semiconductor wafer, the reverse of the wafer is ground by a planarization apparatus such as a back grinder so as to make a thin semiconductor wafer.
However, a fracture layer is formed on the reverse of the semiconductor wafer by the back grinding, and the fracture layer results in lower strength of the semiconductor wafer. In view of the disadvantage, the ground reverse of the semiconductor wafer is processed with an etching process in order to remove the fracture layer.
The semiconductor wafer that is etched after the back grinding as described above is mounted on a wafer frame after separating a protecting sheet, which is adhered for protecting the obverse of the wafer at back grinding. Then, the semiconductor wafer is supplied to a dicing machine while being mounted on the wafer frame, and the semiconductor wafer is diced into individual elements by the dicing machine.
In such a conventional method, the separation of the protecting sheet and the mounting of the wafer on the wafer frame are performed by an operator all manually. However, the semiconductor wafer that is made thin by etching is difficult to handle, and yield is lower.
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of an etching apparatus that can automatically mount the etched wafer on the wafer frame.
In order to achieve the above-described objects, the present invention is directed to an etching apparatus, comprising: an etching part which holds an obverse of a wafer with a chuck by suction, the chuck being movable up and down and rotatable, then supplies etching liquid to a reverse of the wafer while rotating the wafer in a processing vessel so as to etch the reverse of the wafer, then jets a cleaning liquid to the reverse of the wafer while rotating the wafer so as to clean the reverse of the wafer, and then jets air to the reverse of the wafer while rotating the wafer so as to dry the reverse of the wafer; a wafer supply part which supplies the wafer to the etching part; a mount part which receives a wafer frame at a wafer frame receiving position, then moves relatively to an upper part of the processing vessel, then mounts the wafer on the wafer frame by adhering the reverse of the wafer that is transported to the upper part by the chuck to an adhesive sheet together with the wafer frame so as to mount the wafer on the wafer frame, and then returns to the wafer frame receiving position; a wafer frame supply part which supplies the wafer frame to the mount part which is positioned at the wafer frame receiving position; and a wafer frame collection part which collects the wafer frame from the mount part having returned at the wafer frame receiving position.
According to the present invention, the wafer is first supplied to the etching part by the wafer supply part. The obverse of the wafer, supplied to the etching part, is held by suction with the chuck which can move up and down and can rotate. Then, the wafer is rotated in the processing vessel while the etching liquid is supplied to the reverse of the wafer so as to etch the wafer. After the etching is completed, the wafer is again rotated in the processing vessel while the cleaning liquid is jetted to the reverse of the wafer so as to clean the wafer. Then, the cleaned wafer is still again rotated in the processing vessel while the air is supplied to the reverse of the wafer so as to dry the wafer. After the cleaning and the drying of the wafer are completed, the mount part which has received the wafer frame from the wafer frame supply part at the wafer frame receiving position moves to the upper part of the processing vessel. Then, the chuck moves up to the mount part which has moved to the upper part of the processing vessel, and the reverse of the wafer is adhered to the adhesive sheet together with the wafer frame, thereby the wafer is mounted on the wafer frame. The mount part that includes the wafer frame and the wafer mounted on the wafer frame returns to the wafer frame receiving position, and the wafer frame collecting part collects the wafer frame from the mount part that has returned to the wafer frame receiving position. By the process described above, the etched wafer can be mounted on the wafer frame in an automatic manner.


In the fabrication of semiconductor devices, a method of forming a fine pattern on a semiconductor substrate includes the steps of exposing and developing a photoresist deposited on a film of a semiconductor substrate in order to remove selected portions of the photoresist, etching portions of the film left exposed when the selected portions of the photoresist are removed, and subsequently removing any of the photoresist remaining on the semiconductor substrate with dimethylacetamide, or a combination of monoethanolamine and dimethylsulfoxide. Such stripping solutions are capable of removing photoresists in the Deep-UV group as well as the conventionally used photoresists in the I-line group.

1. Field of the Invention
The present invention relates to a method of manufacturing semiconductor devices. More particularly, the present invention relates to a process of stripping photoresist from a semiconductor wafer using a solution of dimethylacetamide or a solution of monoethanolamine and dimethylsulfoxide.
2. Description of the Related Art
In general, the fabricating of semiconductor devices involves the use of photolithography for forming a pattern on a semiconductor wafer.
In photolithography, a photoresist deposited on the semiconductor wafer is selectively removed in a series of processing steps, such as an exposure step, a development step, etc. A pattern designed according to the desired characteristics of the semiconductor device is formed on the semiconductor wafer using the photoresist as a mask.
Photoresists can be classified into two groups: positive photoresists and negative photoresists. Whether a photoresist is considered to be of a positive type or of a negative type depends on the region thereof which is removed after selected portions of the photoresist are irradiated during the exposure process.
That is, the positive type of photoresist is one in which the exposed regions of the photoresist are removed from the semiconductor substrate. The negative type of photoresist is one in which the non-exposed regions of the photoresist are removed from the semiconductor substrate.
On the other hand, photoresists can also be classified according to the wavelength at which the photoresist responds with respect to its exposure and development. Photoresists classified in this way include those of the I-line group, the G-line group, and the Deep-UV group.
When an Hg-Arc lamp is used as the general light source in the semiconductor device manufacturing process, photoresists are classified in the I-line group, G-line and Deep-UV according to the wavelength of light from the spectrum of the Hg-Arc lamp. More specifically, a photoresist in the I-line group responds to light having a wavelength of 365 nm. A photoresist in the G-line group responds to light having a wavelength of 436 nm, and a photoresist in the Deep-UV group responds to light having a wavelength of 248 nm.
In a conventional semiconductor device fabrication process, a positive photoresist in the I-line group is normally used. That is, the regions of a photoresist exposed to light having a wavelength of 365 nm are selectively removed from the semiconductor substrate.
However, photolithography using a positive photoresist in the I-line group has its limits. In particular, such a process can only form a pattern as small as 0.3 .mu.m. Such a process, therefore, is not suitable for manufacturing the highly miniaturized semiconductor devices which are now in demand.
Accordingly, recent semiconductor device fabrication processes employ photoresists in the Deep-UV group. These photoresists can be used to form patterns smaller than even 0.2 .mu.m.
However, photoresists in the Deep-UV are inferior to those in the I-line group in terms of their resistance to light and heat. This is because the constituents of the photoresists in the I-line group and the photoresists in the Deep-UV group, such as the polymer component, the light-reactant, and the solvent, are different from each other.
In fact, photoresists in the Deep-UV group are not widely used in semiconductor device fabrication because no chemical has yet been developed which can completely remove a Deep-UV group photoresist remaining on a semiconductor substrate after the photolithography has been completed.

Method of stripping a photoresist from a semiconductor substrate using dimethylacetamide or a combination of monoethanolamine and dimethylsulfoxide


A secondary of an elevator linear motor includes a highly conductive layer, the layer having a plurality of periodically spaced grooves disposed horizontally therein, the grooves providing space for thermal expansion of the layer and guiding current induced on said layer thereby increasing the efficiency of the motor.

Usually, an elevator's drive sheave and motor are arranged above the elevator car in a machine room. In buildings, where space is at a premium, machine rooms are not desirable.
Hydraulic elevators are driven by a piston which is usually disposed within a cylinder hole beneath the elevator car, thereby obviating the need for a machine room. However, building the hole and maintaining the piston therein is time consuming and expensive. Hydraulic elevators have other drawbacks relative to traction elevators: the rise of the car is limited by the length of the piston; the speed of travel is inferior; and the car weight is not offset by a counterweight making operation relatively inefficient.
Some elevators are driven by a linear motor having a tubular primary element disposed around a tubular secondary element. The linear motor does not require a machine room, as required by a traction elevator, and has no hole, as required by an hydraulic elevator. Also, linear motor driven elevators, relative to hydraulically powered elevators, are energy efficient, operate over a higher rise and are faster. Tubular linear motors typically utilize a secondary element which is hung from the top of the hoistway. At present, it is impractical to hang a secondary element over an extended rise.
UK Patent Application 2,237,555A to Toshiba shows an elevator driven by a linear motor having a flat secondary element and a flat primary element. The secondary element is affixed to the hoistway and avoids the problem of hanging the secondary element from the top of the hoistway. Some elevators have linear motors having highly conductive layers disposed upon the secondary elements thereof for increasing the efficiency of the motor.