A system is for pressure testing a barrier in a well from below. The system has a first barrier, a second barrier located below the first barrier in the wellbore, a confined testing space located between said first and second barriers in the well, and a fluid reservoir. The system further has a pressurizing member for pressurizing fluid from said fluid reservoir and for transferring said pressurized fluid into said confined testing space, a pressure sensor for measuring pressure in relation to said confined space; and a pressure data receiver for receiving data from said pressure sensor. There is also described a method for pressure testing a barrier in a well from below.

In the oil and gas industry, safety is always a major concern. Incidents may have severe consequences, such as witnessed in the aftermath of the Deepwater Horizon catastrophe. To prevent such incidents, barriers placed in wells play a leading role. The well barriers are installed mainly to control fluid flow in the well, and ultimately to prevent a blowout, i.e. an uncontrolled release of formation fluids out of the well after the pressure control system, including one or more barriers, has failed.
A barrier set in a well can be said to have two sides: an uphole side and a downhole side. The purpose of the barrier is typically to prevent fluids from moving from the downhole side of the barrier and to the uphole side of the barrier. Thus, the downhole side can be said to be upstream the barrier and the uphole side to be downstream the barrier.
Herein, all references to "above" and "below" a barrier or any other feature in the well, should be construed as closest to surface and closest to the bottom of the well, respectively.
To ensure that a set barrier is able to withstand a given pressure, it is required to pressure test the barrier. Standards, such as NORSOK D-010 relating to well integrity in drilling and well operations, contain detailed requirements for pressure testing of well barriers such as cement-based and mechanical plugs. NORSOK D-010 specifies that barriers should be tested in the direction of potential flow (i.e. an upstream pressure test). However, in the industry cement plugs are typically tested from above (downstream pressure test) as no technique currently exists to effectively test them from below.
Testing of a well barrier from above has certain shortcomings and disadvantages. Firstly, testing a barrier from above implies testing the barrier's ability to withstand overpressure from above the barrier instead of in the normal direction of flow. However, a successful pressure test from above does not necessarily entail that the barrier would be able to withstand the same pressure from the opposite direction, i.e. from the direction where the pressure will normally come from in operation. Secondly, if a barrier is set above a lower barrier which has already been pressure tested, it can be very difficult to accurately pressure test the upper barrier from above, since being able to differentiate between the two pressure tests relies purely on the volume of fluid above each barrier, and this can often be similar if the two barriers are located at similar depths. Thirdly, a successful pressure test of an upper barrier from above will not be able to give any indications of the integrity of one or more lower barriers in the well.

System and method for testing a barrier in a well from below


In an digital/analog converter having a conversion circuit for converting a digital signal into an analog signal, and an output voltage follower connected to the conversion circuit, a voltage amplitude lowering circuit for lowering an amplitude of power supply voltages applied to the conversion circuit to conform to an amplitude of a linear output of the voltage follower, and a voltage amplitude enlarging circuit for enlarging the amplitude of the output of the voltage follower.

1) Field of the Invention
The present invention relates to a digital/analog (D/A) converter having a D/A portion and an output voltage follower.
2) Description of the Related Art
Recently, as the size of electronic apparatuses has been reduced, D/A converters have been used as semi-fixed resistors for digital tuning, and wide-range output characteristics are required for such D/A converters.
A prior art D/A converter includes a digital/analog conversion circuit and an output voltage follower.
In the above-mentioned prior art, however, since the output voltage follower has a smaller range linear output characteristic than a range defined by two power supply voltages, the linear output characteristic of the entire D/A converter is small. This will be later explained in more detail.

Wide-range linear output digital/analog converter


A flexible, dual ball joint assembly used for increasing the wear life of a mud motor. The ball joint assembly includes an drive shaft with a drive shaft hollow ball joint. An outer circumference of the hollow ball joint includes a plurality of equally spaced apart drive shaft ball bearings. An inner circumference, inside the hollow ball joint, includes a plurality of equally spaced apart drive shaft grooves. Also, the ball joint assembly includes an annular shaped torque coupler with a torque coupler ball joint. An outer circumference of the torque coupler ball joint includes a plurality of equally spaced apart torque coupler ball bearings. The torque coupler ball bearings are received in the drive shaft grooves for providing lateral movement between the drive shaft and the torque coupler. An outer circumference of the torque coupler next to the torque coupler ball joint includes a plurality of torque coupler lobes equally spaced apart therearound. Further, the ball joint assembly includes a sliding torque sleeve used to secure the drive shaft to the torque coupler during the operation of the ball joint assembly.

(a) Field of the Invention
This invention relates generally to an improved mud motor used in directional drilling of oil and gas wells and more particularly, but not by way of limitation, to an improved flexible, dual, constant velocity or CV, ball joint assembly used with an drive shaft for increased wear life of a mud motor.
(b) Discussion of Prior Art
In directional oil and gas drilling down-hole, a drill pipe string includes a mud motor with a fluid drive rotor inside a stator. The rotor and stator are disposed inside the mud motor's housing and is driven by high pressure fluid. The rotor provides high torque and eccentric, rotation motion for driving the mud motor. The mud motor is used for rotating a drill bit at the end of the drill pipe string. Also inside the mud motor housing is a drive shaft. The drive shaft is used for compensating for eccentric lateral movement from the fluid drive rotor as well as a bend in a mud motor housing of up to 3 degrees. Opposite ends of the drive shaft include universal ball joints with ball bearings for making the lateral movement. The subject invention is a substantial improvement of a flexible universal joint at opposite ends of the drive shaft in the mud motor housing to greatly reduce wear under high torque and compression loading.
In U.S. Pat. Nos. 4,772,246 to Wenzel and 5,704,838 to Teale, universal joint assemblies are disclosed and used with a down-hole mud motor. The prior art patent references don't disclose the unique features and function of the subject high torque, dual, constant velocity, ball joint assembly with multiple rings of ball bearings used with a drive shaft inside a down-hole mud motor housing.

High torque, flexible, dual, constant velocity, ball joint assembly for mud motor used in directional well drilling


A processing network comprising a cache configured to store copies of memory data as a plurality of cache lines, a cache controller configured to receive data requests from a plurality of cache agents, and designate at least one of the cache agents as an owner of a first of the cache lines, and a directory configured to store cache ownership designations of the first cache line, and wherein the directory is encoded to support substantially simultaneous ownership of the first cache line by a plurality but less than all of the cache agents. Also disclosed is a method comprising receiving coherent transactions from a plurality of cache agents, and storing ownership designations of a plurality of cache lines by the cache agents in a directory, wherein the directory is configured to support storage of substantially simultaneous ownership designations for a plurality but less than all of the cache agents.

Modern computer systems may rely on multiple interconnected processors to process data. Such processor(s) and/or resulting processor cluster(s) may perform processing operations on substantially the same data concurrently. To reduce system latency, multiple copies of process data may be stored in multiple memory locations. Such a multi-location storage system may result in a need for a coherent memory scheme. A cache coherent memory scheme may be a protocol that may allow multiple memory components, such as caches and/or Random Access Memory (RAM), to maintain local copies of shared data and receive updates when the shared data is modified by other components and/or processes.


There is disclosed an electron shower apparatus which eliminates the adverse effect of a magnetic field on electrons and which provides electrons in sufficient quantity when primary electrons having low energy are employed. In the apparatus, the magnetic field generated by a filament current is decreased or eliminated by pulsing the filament current or by passing a current opposite in direction to the filament current in the vicinity of the filament current.

1. Field of the Invention
The present invention relates to an electron shower apparatus provided as part of an ion implanting apparatus used for the production of semiconductors. The electron shower apparatus is used to prevent electrostatic discharge damage to insulating parts in a sample plate.
2. Description of the Background Art
FIG. 17 schematically shows a conventional ion implanting (irradiating) apparatus which is an ion beam irradiating apparatus disclosed in Japanese Patent Application No. 2-79628 by the applicant of the present invention. Reference numeral 1 designates an electron shower apparatus mounted to a Faraday cup 7; 2 designates a thermoelectronic emission source; 3 designates an electron extracting electrode; 20 designates an opening of the electron extracting electrode 3; 4 designates a decelerating electrode; .21 designates an opening of the decelerating electrode 4; 6 designates a power source for heating the thermoelectronic emission source 2; 8 designates a sample table; 9 designates a sample; 10 designates an ion beam; and 19 designates a power source for applying energy toward the sample 9 to electrons.
FIG. 18 illustrates the movement of an electron emitted from the thermoelectronic emission source 2 of FIG. 17. Reference numeral 22 designates equipotential surfaces formed between the extracting electrode 3 and decelerating electrode 4.
Operations will be described with reference to FIGS. 17 and 18. A decelerating electric field formed between the electron extracting electrode 3 and decelerating electrode 4 in the electron shower apparatus 1 of FIG. 17 is represented by the equipotential surfaces 22 of FIG. 18. An electron e.sup.- 11 extracted from the thermoelectronic emission source 2 by the extracting electrode 3 enters the decelerating electric field perpendicularly to the axis of the ion beam 10. Since the electron 11 is decelerated perpendicularly to the equipotential surfaces 22 in the decelerating electric field, an emitting angle .alpha. of the electron 11 is expressed as: ##EQU1## where .theta. is an inclination angle of the equipotential surfaces 22 in the vicinity of the openings 20, 21 of the extracting and decelerating electrodes 3, 4 to the axis of the ion beam 10; Va is an extraction voltage; and Vd is a deceleration voltage.
The electron emitted from the decelerating electrode 4 and applied to the ion beam 10 has a component of velocity toward the sample 9. The generation of a slight potential at the power source 19 for applying energy toward the sample 9 to the electron enables the electron to travel toward the sample 9 without difficulty.
Relatively low energy electrons (primary electrons) are thus transported directly toward the sample, whereby the sample 9 charged positive by ions is neutralized while the sample 9 is prevented from being charged negative by the electrons.
Such a conventional process, however, has a problem in that a magnetic field generated by a heating current traps the low energy electrons so that the electrons in sufficient quantity to neutralize the positive charged sample 9 are not transported to the sample 9. The reason is discussed below. When the thermoelectronic emission source 2 is a bar-like tungsten filament of 1 mm in diameter, a filament heating current of 40 A or more in DC is required. A magnetic field B.sub.0 generated by the filament heating current outside of the filament is expressed as: EQU B.sub.0 (r)=.mu..sub.0 I/(2.pi.r) (2)
where .mu..sub.0 is a magnetic permeability in a vacuum; I is a filament current; and r is a distance from the center of the filament.
The magnetic fields calculated from Equation 2 are 160 gauss and 40 gauss in the positions where I=40 A and r =0.5 mm and where I=40 A and r=2 mm, respectively.
The Larmor radius r.sub.L of the electron having energy of E eV in the position where the magnetic field is B gauss is expressed as: ##EQU2## where m is the mass of electron; and e is an elementary electric charge.
The Larmor radius is approximately 15 mm where the magnetic field is 40 gauss and electronic energy is 300 eV, and the Larmor radius is approximately 5 mm where the magnetic field is 40 gauss and electronic energy is 30 eV. The electronic energy of 300 eV is primary electronic energy frequently used in an electron shower of the type in which secondary electrons are utilized, and the electronic energy of 30 eV is primary electronic energy to be used in an electron shower of the type in which primary low energy electrons are utilized.
The Larmor radius of 15 mm at the energy of 300 eV is three to eight times larger than the spacing of 2 to 5 mm between the electrodes which is adopted in the practical electron shower, and the Larmor radius of 5 mm at the energy of 30 eV is only as approximately large as the spacing to a little over twice larger than the spacing. This provides the indication that the electron having the energy of 30 eV (low energy) is more susceptible to the magnetic field than the electron having the energy of 300 eV. When the primary electron having low energy (e.g., 30 eV or less) is used, an electron orbit is largely bent by the magnetic field, so that the electron strikes the electrodes. The electron is not extracted efficiently or the orbit of the extracted electron is largely bent. As a result, it is considered that the electrons in sufficient quantity are not transported to the target sample.
In the electron shower apparatus of the prior art, in practice, a current of several tens mA passes through the decelerating electrode opening 21 where the extraction voltage is 300 V and the deceleration voltage is 300 V (without deceleration), and a current of only 1 mA or less passes through the opening 21 where the extraction voltage is 300 V and the deceleration voltage is 30 V. However when the filament heating current is changed to an alternating current (sine wave), a peak of the current of approximately 20 mA is observed at the point where the filament heating current is zero when the extraction voltage is 300 V and the deceleration voltage is 30 V. It is apparent from these facts that the magnetic field generated by the filament current exerts adverse effect on the low energy electrons.
The quantitative result of the influence of the magnetic field generated by the filament current on neutralizing electrons is easily derived from an equation of motion of charged particles and the like. Detailed description thereof will be omitted herein.
Decrease in cross-sectional area of the filament 2 to increase the resistance of the filament 2 enable the filament heating current to decrease. This process, however, has disadvantages. One of the disadvantages is that the thin filament 2 is prone to thermal deformation and short lifetime. This is a demerit in long-time, stable, continuous drive of the electron shower apparatus 1. The other disadvantage is a large potential difference across the filament 2 because of a large proportion of increase in resistance compared with the proportion of decrease in current. This means large scatter of electron energies. This disadvantage prevents the electrons from going low energy and causes deviation of electron distribution. The filament 2, when shortened, prevents the disadvantage, but must be prepared in plurality for ensuring a shower current, resulting in a complicated structure.

Electron shower apparatus including filament current control


Inhibitors of 15-lipoxygenase (15-LO) are useful to treat and prevent inflammation or atherosclerosis. Preferred inhibitors have a ratio of 5-LO to 15-LO inhibitory activity of at least about 10 or more. Typical 15-LO inhibitors have the formula ##STR1## wherein R.sup.13 is phenyl, 4-chlorophenyl, 4-fluorophenyl, 4-nitrophenyl, 2,5-dichlorophenyl, 2-furanyl, 2-thienyl, 3-pyridyl, or 4-pyridyl.

Atherosclerosis is a multifactorial disease characterized by excessive intracellular lipid deposition in macrophages, leading to formation of foam cells. The accumulation of lipid-loaded foam cells in the subendothelial space leads to formation of fatty streaks, which are the early atherosclerotic lesions.
Oxidative modification of lipids, specifically low-density lipoprotein, has been implicated as a major process in foam-cell formation.
Lipoxygenases are nonheme iron-containing enzymes that catalyze the oxygenation of certain polyunsaturated fatty acids such as lipoproteins. Several different lipoxygenase enzymes are known, each having a characteristic oxidation action. One specific lipoxygenase, namely 15-LO, has been detected in atherosclerotic lesions in mammals, specifically rabbit and man. The enzyme, in addition to its role in oxidative modification of lipoproteins, is important in the inflammatory reaction in the atherosclerotic lesion. Indeed, 15-LO has been shown to be induced in human monocytes by the cytokin IL-4, which is known to be implicated in the inflammatory process.
Another class of lipoxygenase enzymes is 5-lipoxygenase (5-LO). While this enzyme causes oxidation of unsaturated fatty acids, it primarily is responsible for inserting oxygen on position 5 of arachidonic acid. Other lipoxygenases are known; one of the most common and abundant being 12-lipoxygenase (12-LO).
We have now found that inhibitors of 15-LO are especially useful to prevent and treat inflammation and atherosclerosis. While there are several lipoxygenase enzymes, specific inhibition of 15-LO is critical in the inflammatory and atherosclerosis process. All that is required according to this invention is to administer a 15-LO inhibitor, and especially one that is a specific 15-LO inhibitor.
Several classes of organic compounds are 15-LO inhibitors.
Tetracyclic indole and benzopyranoindole compounds are potent 15-LO inhibitors. U.S. Pat. No. No. 3,388,133 describes benz[b]indolo[2,3-d]-thiopyrano and pyrylium salts as antibacterial and antifungal agents. U.S. Pat. No. 4,132,714 describes a process for making chromenoindoles, which are said to be useful as color-forming agents. U.S. Pat. No. 4,797,495 discloses a wide variety of benzocarbazoles which are said to be antitumor agents. Similarly, benzimidazoles are well known as antiviral agents. U.S. Pat. No. 4,293,558 describes various 1-thiazolinyl-2-aminobenzimidazoles, and U.S. Pat. No. 4,243,813 describes 1-sulfonyl-benzimidazoles. None of those compounds have been described as inhibitors of 15-LO, and none have been utilized in treating inflammation or atherosclerosis. All of these compounds are 15-LO inhibitors and can be employed in the method of this invention.
We have now discovered that compounds which are effective inhibitors of 15-LO are useful in treating and preventing inflammation and atherosclerosis.

Method for treating and preventing inflammation and atherosclerosis


It becomes difficult to perform the optimum equalization signal processing in coherent receiving systems if a channel response in an optical fiber transmission line includes a factor without temporal centrosymmetry, therefore, an equalization signal processor according to an exemplary aspect of the invention includes an equalization filter means configured to receive digital signals by coherent receiving systems; a coefficient control means configured to control coefficients defining characteristics of the equalization filter means; a significant coefficient holding means configured to hold significant coefficients of significant values among initial values of the coefficients; a significant coefficient positioning means configured to determine a significant coefficient position, a position of the significant coefficients in the initial values, so that equalization characteristics of the equalization filter means may be optimized; and a significant coefficient setting means configured to allocate the significant coefficients to the significant coefficient position.

It is important in long-haul optical communications to realize high spectrum utilization efficiency and, accordingly, communication systems using multi-level modulated signals or polarization-multiplexed signals have been developed. Since coherent receiving systems can receive multi-level modulated signals and polarization-multiplexed signals, they have been used in a large number of communication systems in recent years. It is possible in the coherent receiving system to obtain the information not only on the amplitude of the received light but also on the phase of it because the received light is detected by a photodetector after having interfered with local oscillator light. Concerning the signal obtained by using the coherent receiving system, therefore, it is known that by means of the digital signal processing the signal degradation while transmitting can be compensated and the obtained signal can be demodulated. The digital signal processing technology mentioned above, therefore, has become important.
By using the digital signal processing technology, it is possible to compensate a received signal with a temporal spread of the optical signal occurring due to the polarization mode dispersion, for example. The polarization mode dispersion means a difference in the propagation velocity in an optical fiber transmission line between polarization modes which is caused by a deviation from an exact circle in a fiber, and the like. Phenomena having polarization dependence in a transmission line, such as polarization mode dispersion and polarization rotation, have frequency dependence and vary temporally due to a different kind of external action such as pressure applied to a fiber. It is necessary, therefore, to perform the digital signal processing adaptively in order to equalize received signals deteriorated by a factor with such temporal variation.
It is possible to perform adaptive equalization signal processing in the time domain by using a finite impulse response (FIR) filter. In optical communication technologies, a butterfly-structured FIR filter as shown in FIG. 9 is generally employed in order to equalize signals deteriorated by a factor dependent on the polarization. The coefficients of the FIR filter are adaptively adjusted by a feedback control based on the CMA (Constant Modulus Algorithm) method or the DDLMS (Decision Directed Least Mean Square) algorithm, for example.
An example of a method for controlling a butterfly-structured FIR filter is described in Non Patent Literature 1. As shown in FIG. 9, an X-polarization input EX(k) and a Y-polarization input EY(k) are input into a related butterfly-structured FIR filter 900, whose outputs EX(k) and EY(k) are expressed as follows:Ex(k)=hxxT·EX+hxyT·EY=Σm=0M−1[hxx(m)EX(k−m)+hxy(m)EY(k−m)]  (1)Ey(k)=hyxT·EX+hyyT·EY=Σm=0M−1[hyx(m)EX(k−m)+hyy(m)EY(k−m)]  (2)
Here, hxx=[hxx(0) . . . hxx(M−1)] and the like are tap coefficients of the FIR filter, and M represents the tap length. The superscript "T" denotes a transposed matrix. When the CMA method is used, these tap coefficients are controlled on the basis of the formulae (12) to (15) described in Non Patent Literature 1. The X-polarization input and Y-polarization input are weighted and summed by using the coefficients controlled by the CMA method. This enables deteriorating factors dependent on the polarization to be cancelled, and the compensation process is accomplished. As a result, proper receiving processes can be realized.
Thus, the butterfly-structured FIR filter is employed in the coherent receiving system using the digital signal processing. If the tap length of the FIR filter increases, the calculation amount necessary for updating the tap coefficients increases accordingly and this requires a large amount of circuit resources. It is desirable, therefore, to shorten the tap length of the FIR filter as much as possible. On the other hand, in order to compensate a temporal spread of a signal due to the polarization mode dispersion by using the butterfly-structured FIR filter, it is necessary to realize an inverse response of the temporal spread by means of the FIR filter. If the tap length of the FIR filter is finite, however, there is a possibility that an intended response cannot be realized.
Non Patent Literature 2 describes an example of the polarization demultiplexing in a coherent receiver which is performed by controlling the coefficients of a butterfly-structured FIR filter using the CMA method. As described in Non Patent Literature 2, in general, a response of the polarization mode dispersion, which is a main factor to be compensated by a butterfly-structured FIR filter, can be expressed by a unitary matrix, and so the inverse response can also be expressed by a unitary matrix. Accordingly, the following relation holds for the inverse response.hyy(t)=hxx*(−t),hxy(t)=−hy*(−t)  (3)
Here, the superscript "*" represents a complex conjugate. From the relation of formula (3), the following formulae hold:|hxx(t)|2+|hyy(t)|2=|hxx(−t)|2+|hyy(−t)|2  (4)|hxy(t)|2+|hyx(t)|2=|hxy(−t)|2+|hyx(−t)|  (5)
As can been seen from formulae (4) and (5), the magnitude of the inverse response of the polarization mode dispersion has a kind of temporal centrosymmetry. In a case where the tap coefficients of a butterfly-structured FIR filter are adaptively controlled, taking the above relationship into account, initial values of the tap coefficients are generally set so that significant coefficients may be allocated for the center tap of the FIR filter and the other coefficients may be set to "0". Here, the significant coefficients correspond to a Jones matrix representing input-output relations for respective polarization signals, which is realized by the butterfly-structured FIR filter. As described in Non Patent Literature 2, for example, the initial values of the tap coefficients of the butterfly-structured FIR filter can be set as follows:hxx=[0001000],hxy=[0000000],hyx=[0000000],hyy=[0001000]
Here, it is assumed that the polarization rotation and temporal spread due to the transmission do not arise initially, and the tap length M is set at 7. In this example, an identical Jones matrix expressed by the following formula (6) is set at hxx(3), hxy(3), hyx(3), and hyy(3) of central tap coefficients in the FIR filter.
                              (                                                                                h                    xx                                                                          (                    3                    )                                                                                h                    xy                                                                          (                    3                    )                                                                                h                    yx                                                                          (                    3                    )                                                                                h                      yy                                                                                (                      3                      )                                                                                )                =                  (                                                    1                                            0                                                                    0                                            1                                              )                                    (        6        )
Then, it is possible to perform the adaptive equalization signal processing by using tap coefficients which have converged by means of the CMA method.
On the other hand, Patent Literature 1 describes an example of a compensation device to compensate a distortion having occurred in an optical fiber by using optical elements. The related compensation device described in Patent Literature 1 includes a wide-band adaptive optical equalizer, an optical feedback monitor, and a controller. The wide-band adaptive optical equalizer includes a plurality of tunable optical filter units, each of which includes a beam splitter and a differential delay element. The optical feedback monitor samples signals passing through the wide-band adaptive optical equalizer. It is said that the controller sets initial control parameters of the tunable optical filter unit and controls the wide-band adaptive optical equalizer by using the control parameters which are determined on the basis of sampling results of the optical feedback monitor. However, since the polarization mode dispersion varies temporally and it is difficult for the optical element to track the variation, it is difficult for the related compensation device to compensate the polarization mode dispersion.
Patent Literature 1: Japanese Patent Application Laid-Open Publication (Translation of PCT Application) No. 2005-520391 (paragraphs [0047] to [0087])
Non Patent Literature 1: S. J. Savory, "Digital filters for coherent optical receivers," Optics Express Vol. 16, No. 2, 2008, pp. 804-817.
Non Patent Literature 2: L. Liu et al., "Initial Tap Setup of Constant Modulus Algorithm for Polarization De-multiplexing in Optical Coherent Receivers," Optical Fiber Communication Conference, OSA Technical Digest (CD) (Optical Society of America, 2009), paper OMT2.

Equalization signal processor, optical receiver including the same, and method for equalization signal processing


A dental handpiece provided with a handle and a head on one end thereof in which a turbine rotates at high speeds and accommodates a cutting bur having an axial through opening to direct a preferably hygienic coolant directly through the cutting end of the bur, while the opposite end of the bur, on the interior of the head, is highly polished and absolutely flat for rotating engagement with one surface of a rotary liquid seal including a seal member of very hard substance in combination with a pliable compressible member engaging the opposite surface of the seal member, the combination being housed within a recess extending upwardly in a push button on the head or other finger-operated bur release mechanism on the head and having coaxial fluid openings communicating axially with the through opening in the bur and fluid passage in the push button leading from a fluid supply conduit in the handle. The fluid preferably consists of one or more of several chairside selectable pharmaceutical ingredients added to a coolant for discharge into a cavity being cut in a tooth by the handpiece.

The preparation of tooth cavities for acceptance of filling materials normally is a painful experience unless pain-relieving anesthetic drugs, such as Lidocaine injections, or nitrous oxide gas inhalation is first applied prior to the dental preparation. In conjunction with cavity preparation, it is customary for a dental assistant to spray a jet of water onto the tooth being cut by the bur of the handpiece and this frequently clouds or fogs the area being prepared so that the dentist has difficulty seeing where the cutting is occurring. Many modern handpieces operated at speeds up to 400,000 rpm in order that heavy cutting pressure is not required. However, at such speeds, heat can be generated up to 450.degree. F. with a bur pressure of 32 grams, for example, at 170,000 rpm.
It has been found that a minimum water flow rate of 16 cc/minute is necessary to form a stream with force enough to reach the bur tip area in a commercial handpiece having as many as four or five jets of flushing water. This situation is responsible for such aforementioned fogging of the dental operation site.
Current types of handpieces which have axial through passages present difficulties when endeavoring to restrict cooling liquid by such liquid tending to enter the head and bearings of the turbine and flushes the lubricant thereof.
Another difficulty with such aforementioned through passages in burs in a handpiece is some community water supplies carry impurities and chemicals that may be harmful to patients and can clog the passage in the bur. Also, when using cooling sprays of water, when the dentist stops the flow water, there is a tendency for a suck-back or retraction function to occur in which contaminants in a patient's mouth may be drawn back into the head of the handpiece where they remain and may even migrate into the fluid supply conduits or hoses. Hence, when used with the next patient, any such contaminants can be discharged into said next patient's mouth.

Dental handpiece, bur mount operating system


An active headrest assembly for a vehicle includes a headrest supported by a seat back frame. An active plate is connected to the headrest and has guide slots defined therein. Guide pins are inserted through the guide slots to slide along the guide slots. A lumbar unit has a support wire secured to the guide pins and is rotatably connected to the lower end of the seat back frame. A returning unit elastically connects the active plate and the lumbar unit with each other.

1. Field of the Invention
The present invention relates to an active headrest assembly for a vehicle which has a lumbar unit cooperating with an active plate.
2. Description of the Prior Art
As is well known in the art, an active headrest assembly for a vehicle serves as a device in which a headrest cooperates with an active plate installed in a seat back to help protect an occupant's head and neck against neck injury.
A conventional active headrest assembly includes an active plate, which is transversely arranged in the seat back frame of a seat back, and a headrest, which is connected to the active plate to rotate around the upper end of the seat back frame. If shock is generated when the vehicle is in a collision, rearward force is applied to the active plate by an occupant leaning on the seat back. As the active plate is rotated rearward by the application of the force, the headrest is rotated forward. By this fact, the headrest comes into close contact with the rear portion of the occupant's head and prevents the occupant's neck from being injured.
However, in order to ensure the reliable functioning of the headrest, the active plate must project forward to some extent. The projecting active plate may decrease the riding comfort of an occupant who leans with his or her back on the seat back.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.


A technique of providing user guidance for surgical navigation is provided. A method implementation of the technique includes obtaining a predetermined spatial relationship between an optical tracking pattern and a through-hole extending through an implant, obtaining image data of the optical tracking pattern acquired by an imaging unit attached to a surgical instrument, obtaining a spatial relationship between the surgical instrument and the imaging unit at a point in time when the image data have been acquired, determining a spatial relationship between the surgical instrument and the through-hole, obtaining a plurality of predefined spatial relationships between the surgical instrument and the through-hole, and triggering simultaneous display of an indication of the plurality of predefined spatial relationships and an indication of the spatial relationship between the surgical instrument and the through-hole.

Surgical navigation generally provides a surgeon with information useful for surgery. For example, a pose (i.e., at least one of a position and an orientation) of a surgical is instrument (e.g., a chisel, a drill, a trocar, a screwdriver, a pointer or the like) can be visualized relative to patient image data. The patient image data may be two- or three-dimensional image data of a patient acquired using a medical image acquisition technique such as computed tomography or magnetic resonance imaging. A tracking system may be used to track the pose of the surgical instrument relative to a body of the patient by localizing trackers attached to the surgical instrument and the body, respectively.
In some cases, a pose of an implant (e.g., a bone plate, an artificial organ or the like) relative to at least one of the body and the surgical instrument may be of interest to the surgeon. For example, a bone plate may need to be screwed in a desired pose to a bone of a patient, by screwing fixation screws through respective holes in the bone plate. The bone to which the bone plate is to be attached may lie beneath (e.g., critical) anatomical structures of the body of the patient which shall not be injured during surgery. Especially in these cases, minimal-invasive surgery may be advantageous.
In such minimal-invasive surgery, the bone plate may be inserted through a narrow opening in the body of the patient and be positioned on the bone in the desired pose. The bone plate in the desired pose may not be visible to at least one of the surgeon and the tracking system. Thus, for positioning the bone plate relative to the body of the patient, a placement instrument, which may be attached relative to the bone plate in a predetermined spatial relationship, may be tracked by the tracking system. The placement instrument may be used by the surgeon to move the bone plate into the desired pose and may comprise a tracker.
After placement of the bone plate in the desired pose on the bone of the patient's body, fixation screws may need to be screwed through the respective holes in the bone plate to fix the bone plate onto the bone. As mentioned before, the implant, and, consequently, also the holes of the bone plate, may not be visible to at least one of the surgeon and the tracking system after placement of the bone plate in the desired pose. Nevertheless, the pose of the implant relative to the patient's body may still be determined by the tracking system by tracking at least one tracker attached to the placement instrument and at least one tracker attached to the patient's body.
In order to guide the surgeon, information of the relative pose between the surgical instrument and a hole in the bone plate may be advantageous. Providing such information requires determining a relative pose between the surgical instrument and the bone plate.
In some cases, simultaneous visibility of trackers attached to the placement instrument and the surgical instrument may be blocked, for example by an arm of the surgeon. It may therefore be advantageous to ensure a good visibility of these trackers at all times, for example when a screwdriver is being used to screw the fixation screws though the respective holes of the bone plate.

Technique for providing user guidance in surgical navigation


A hydraulic pressure supply system of an automatic transmission for a vehicle which generates low hydraulic pressure and high hydraulic pressure using oil stored in an oil pan and supplies the low hydraulic pressure and the high hydraulic pressure respectively to a low pressure portion and a high pressure portion. The system includes a low-pressure hydraulic pump driven by a first power source so as to pump the oil stored in the oil pan, generating the low hydraulic pressure, and supplying the low hydraulic pressure to the low pressure portion, and a high-pressure hydraulic pump driven by a second power source and fluid-connected to the low-pressure hydraulic pump so as to receive the low hydraulic pressure from the low-pressure hydraulic pump, changing the low hydraulic pressure into the high hydraulic pressure, and supplying the high hydraulic pressure to the high pressure portion.

1. Field of the Invention
The present invention relates to a hydraulic pressure supply system of an automatic transmission for a vehicle. More particularly, the present invention relates to a hydraulic pressure supply system of an automatic transmission for a vehicle which can improve safety and reliability as a consequence of operating a high-pressure hydraulic pump by driving torque of an engine when the high-pressure hydraulic pump does not operated due to failure of the high-pressure hydraulic pump.
2. Description of Related Art
Recently, vehicle makers direct all their strength to improve fuel economy due to worldwide high oil prices and strengthen of exhaust gas regulations.
Improvement of fuel economy may be achieved by improving power delivery efficiency in an automatic transmission, and improvement of the power delivery efficiency may be achieved by minimizing unnecessary power consumption of a hydraulic pump.
A recent automatic transmission is provided with a low-pressure hydraulic pump and a high-pressure hydraulic pump so as to improve fuel economy. Therefore, hydraulic pressure generated by the low-pressure hydraulic pump is supplied to a low pressure portion (i.e., a torque converter, a cooling device, and a lubrication device), and hydraulic pressure generated by the high-pressure hydraulic pump is supplied to a high pressure portion (i.e., friction members selectively operated when shifting).
In further detail, general hydraulic pressure of the automatic transmission is generated for the low pressure portion (i.e., generated by the low-pressure hydraulic pump), and hydraulic pressure demanded by the high pressure portion is generated by the high-pressure hydraulic pump and then is supplied to the high pressure portion.
Since power consumption for driving the hydraulic, pumps can be minimized, fuel economy may be enhanced. In addition, since a load applied to the hydraulic pumps is reduced, noise and vibration may be reduced and durability may be improved.
In a conventional hydraulic pressure supply system, the low-pressure hydraulic pump and the high-pressure hydraulic pump are driven by one drive shaft or the low-pressure hydraulic pump is driven by driving torque of an engine and the high-pressure hydraulic pump is driven by driving torque of a motor.
In a case that the low-pressure hydraulic pump and the high-pressure hydraulic pump are driven by one drive shaft, however, it is impossible to control rotation speeds of the low-pressure hydraulic pump and the high-pressure hydraulic pump independently. In addition, since the high-pressure hydraulic pump discharges the maximum pressure demanded by a transmission, unnecessary power loss may occur.
On the contrary, in a case that the low-pressure hydraulic pump is driven by the driving torque of the engine and the high-pressure hydraulic pump is driven by the driving torque of the motor, the motor may not operate due to failure of the motor or lack of SOC of a battery
In this case, the hydraulic pressure is not supplied to the high pressure portion and the transmission may be damaged.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Hydraulic pressure supply system of automatic transmission


The present invention provides a method enabling segregation of the various ingredients making up the polymer based products into component product streams and collection of these component streams so as to form individual product streams. Thus, according to this invention there is provided a process for purposefully segregating polymer-polymer and polymer-additive mixtures. The process for segregating the various combinations of components may be advantageously used on the one hand for the production of separate product streams from a mixture of polymers or polymer-additives in, for example, recycling of waste plastic based products, or on the other hand, in the production of polymer-polymer or polymer-additive layered structures exhibiting preselected spatial segregation of the various components. In its simplest form, the polymer segregation part of the process consists of a tube added to an extruder. During segregation, polymer layers containing different blend compositions are formed. Operating conditions are selected to enhance differences in viscosity between polymer components. This includes addition of low viscosity grades of one of the polymer components present to encourage migration of that component to the high shear region of the flow. Segregation may occur in either the extruder or in a tube added onto the end of the extruder, or in both. Preferential segregation of additives into one or more of the polymer layers can also be effected. Addition of components which attract the additives to be segregated provide a method of segregating a wide variety of additives.

Description of the Prior Art
The Segregation Process
Polymer (and additive) segregation during melt flow of mixtures is a phenomenon which is generally considered a serious problem in the polymer industry because homogeneous mixtures are associated with good performance properties of the finished product. When a mixture of two immiscible polymers are flowing together in a system, the polymer with the lower viscosity will migrate to the region of higher stress. Although a variety of variables can affect the migration, the effect is often attributed to the "laziness of nature" or the "principle of energy minimization". Shear stress is the product of viscosity and shear rate. In fluid flow through a tube for example, the high shear rate area is adjacent to the wall of the tube and the low shear rate area is at the centre of the tube so that in this case, the low-viscosity component migrates towards the wall. The rate of this process depends upon the rate of change of stress across the tube.
The term additives in this document refers to: species previously added to improve performance of a finished product and no longer desirable in the case of recycling of the spent product; species previously inadvertently introduced into the polymers; species which appeared as a result of the manufacturing process (e.g. catalyst particles or microgel); species which have been added so that they can purposefully be located in a particular part of the polymer (e.g. a core of carbon particles may be desired). Additives can be soluble or insoluble in the polymer mixture. Additives of many types can segregate during flow. "Blooming", "bleeding" and "migration" are terms often used to describe the undesired segregation of plasticizers, dyes, etc. in polymer. The term polymer mixture in this document refers to any combination of polymers together or polymers and additives together.
Migration of particulate additives towards the centre of a tube during flow of particle in liquid suspensions through a tube can occur. One explanation for this effect is that any particle in the stream will have a slightly higher velocity on one side of it (the side closer to the axis of the tube) than on the other side. This causes a difference in pressure ("the Magnus effect") which pushes the particle towards the centre of the flow stream. Particle shape, particle size, particle deformability, particle concentration and the non-newtonian, viscoelastic nature of polymer melts provide additional variables. The effect causes difficulties in attempts to measure the viscosity of particle suspensions. Also, migration of filler particles during injection molding has caused important non-uniformities in molded parts.
There are a few areas where segregation is desired and used. The addition of water to heavy viscous crude oil in long pipelines has long been known to greatly reduce the pressure drop and hence the pumping cost. The water has much lower viscosity than the crude oil and therefore migrates to the wall of the pipe where it functions as a lubricant. Additives such as lubricants, slip agents and mold release agents function because they migrate to the surface of the polymer during processing.
Extrusion of polymer blends to form laminar structures without co-extrusion is receiving increased attention. In the publications H. Garmabi and M. R. Kamal, "The Development of Laminar Morphology In Extruded Polyethylene/Polyamide Blends", Proceedings Annual Technical Meeting Of Plastics Engineers (ANTEC'95), Boston, Mass., May 7-11, 1995; and G. W. Lohfink and M. R. Kamal, "Morphology And Permeability In Extruded Polypropylene/Ethylene Vinyl-Alcohol Copolymer Blends", Polym. Eng. Sci., 33, 1404-1420 (1993) showed that such structures were formed in the converging portion of the die unit attached to the extruder. They emphasize the need for equal viscosities of the polymer components in order to obtain the desired structures. In contrast to their approach, in the process to be described herein, differences in viscosity are desirable to segregate polymers because they are used to obtain desired structures through migration of the dispersed phase.
Since with these few exceptions, segregation is considered undesirable, the overwhelming bulk of prior art is directed at improved mixing of polymers and additives. This invention views segregation as desirable and provides a process for purposefully inducing segregation of polymers and additives.
Generation of Desirable Separate Product Streams from a Mixture of Polymers
Polymers, especially synthetic plastics, can contain undesired components, or higher concentrations of normally desirable components, that impair performance properties. These components are typically other polymers and additives (e.g. pigments and fillers). The situation is particularly acute for recycled plastics because they often originate from diverse sources. In recycled plastics the components of most interest are the types of polymers present. Thus, in conventional processing of such plastics, the waste is sorted manually according to the type of plastic. This is followed by washing, grinding, extrusion and pelletizing separately for each type.
The field of waste recycling is an area of considerable social and economic concern. The economic viability of the industry depends upon development of effective and efficient sorting methods. Sophisticated methods currently under study directed at solving this problem include the use of near infrared spectroscopy with neural network software to speed identification to enable rapid (possibly robotic) sorting. Triboelectric separation of comminuted waste, sink-float procedures based upon density differences, use of powder hydrocyclones, solvent techniques based upon the differing solubility of polymers in different solvents, and the use of chemical markers for identification are all methods presently being investigated in this area.
A major drawback in plastic waste recycling is that at present none of these methods provide satisfactory segregation. The most common method, manual sorting, is highly manpower intensive and expensive. Also, separating polymer waste composed of intimately mixed blends of components or of laminated components is not possible with current methods, except perhaps those that are solvent based. For those, solvent recovery and dissolution times are issues. Therefore, it would be very advantageous to provide a simple and economical method for segregating various components of polymer products.
Formation of Desirable Polymer and Polymer-Additive Structures
Polymer products often demand specific structures. In the packaging industry, for example, multiple layer structures are common as they are required to provide gas barriers and the like. These layered structures are traditionally coextruded using several extruders and associated special dies. In recent years there has been a recognition that extrusion of polymer blends can sometimes form such structures. For example, U.S. Pat. No. 4,410,482 issued to Subramanian on Oct. 18, 1983 discloses that extrusion of a blend of polyolefin, condensation polymer and compatibilizer can be accomplished so as to elongate the dispersed polymer phase to form a multi-layer structure. It is emphasized that the dispersed phase should not have too large a particle size. More recently, U.S. Pat. No. 5,1888,784 issued to Kamal et al. teaches dispersed "bodies" of ethyl vinyl alcohol dispersed in polypropylene are elongated using a die unit to obtain a laminar structure including overlapping layers of the dispersed polymer in the matrix. In that case different screw designs are used to affect the dispersion and the die unit is used to lengthen the dispersed bodies in different directions. All of this prior art emphasizes the presence of a dispersed phase and the stretching of the shape of the dispersed phase in a die. As mentioned above, most recently Garmabi and Kamal (1995) have emphasized the importance of equal viscosities in the two polymer phases so that the dispersed bodies are more deformed in the die so that larger areas are obtained in the laminar layers.
In addition to layered structures of various polymers, structures incorporating various additives as layers can also be important. One notable application is in the formation of electrically conductive polymer structures. Polymers with resistivities <10.sup.6 ohm-cm are considered to be conductive polymers. Conductivity of a polymer can be the result of (a) conjugated bond structures which when activated provide mobile electron clouds or (b) the presence of electrically and/or thermally conductive additives. Examples for such additives include, conducting carbon black (CB), metal powders (Fe, Al), metal fibers (Al, SiC), metal coated glass fibers and hollow glass spheres. These additives are mixed with the polymers during processing in sufficient concentrations to form continuous conducting pathways in the polymer matrix. The matrix polymers employed are decided mainly by the application. Polymers often include non polar elastomers such as polyisobutylene, polyisoprene and conventional engineering plastics such as polycarbonate, ABS etc. and blends thereof. Application of such filled conductive polymers include, electromagnetic interference shielding (EMI), radar frequency jamming, antistatic applications and circuit protection in microelectronics.
In most of these applications, it is not necessary to have the whole matrix conductive, but one conductive layer will be sufficient serve the purpose. By suitably selecting a bi- (or multi) component polymer system such that conductive particles will preferentially migrate to one of the polymer phases (say the core as in an injection molded article) and the other phase forming an insulating shell around the core, could be constructed. Such in situ core-shell conductive-insulating structures have significant commercial potential including the production of electronic items. This technology is all the more desired as it may help retain the same amount of surface finish as without fillers, by reducing the material cost, by obviating multistage processing.
It would therefore be very advantageous to provide a method of producing polymer based layered products which does not require coextrusion of the various constituents.


A readily formable flat steel product has a ductile edge layer that is from 10 to 200 μm thick and has a ductility greater than a ductility of an inner core layer of the flat steel product. The readily formable flat steel product is produced by annealing a flat steel product having a C content of from 0.1 to 0.4% by weight in a continuous furnace. The annealing is carried out under an annealing atmosphere that contains from 0.1 to 25% by vol. of H2 and H2O, with the balance being N2 and technically unavoidable impurities. A dew point is between −20° C. and +60° C., and a ratio of H2O/H2 is a maximum of 0.957. In the course of the annealing, the flat steel product is heated to a holding temperature of from 600 to 1100° C. and for a holding time of from 10 to 360 seconds.

1. Field of the Invention
The invention relates to a method for producing a flat steel product which can be readily formed and which has a C content of from 0.1 to 0.4% by weight, wherein the flat steel product is subjected to an annealing treatment in a continuous furnace.
The invention further relates to a correspondingly produced flat steel product and a method for producing components from such a flat steel product.
2. Background of Related Art
Flat steel products of the type in question in this instance are required in particular for the production of bodywork and chassis components for motor vehicles. In this instance, extremely high demands are placed on the flat steel products in terms of their forming properties. This relates to both cold and hot-formability.
The hot forming of galvanised flat steel products to form high-strength or extremely high-strength steel components is particularly problematic. With such steel components, the protective coating which is generally based on zinc or a zinc alloy provides sufficient cathodic corrosion protection.
However, if a steel sheet which is provided with a metal corrosion protection coating, for the hot forming and hardening operation which may be carried out subsequently or in combination with the hot forming, must be heated to a temperature which is above the melting temperature of the metal of the protective coating, there is a danger of so-called "liquid metal embrittlement". This embrittlement of the steel occurs when molten metal of the coating enters the notches which are formed on the surface of the respective flat steel product during forming. The liquid metal which reaches the steel substrate is precipitated there at the grain boundaries and thus reduces the maximum tensile and compressive stresses which can be taken up.
The danger of liquid metal embrittlement with higher-strength and high-strength steels which have only limited ductility and which consequently have a tendency to form cracks near the surface when they are formed has been found to be particularly critical.
From JP 60-159120 A it is generally known that the bending properties of a steel sheet can be improved by means of a decarbonisation treatment, by means of which there is produced an edge layer which is close to the surface, is from 20 to 100 μm thick and has a reduced C content with respect to the core region of the steel sheet. However, this measure in this prior art has no connection to steel sheets which are covered with a metal protective coating, nor does it relate to higher-strength steels or high-strength steels with C contents of at least 0.1% by weight.
The tendency for decarbonisation of a carbon-containing steel alloy results from the oxidation behaviour of the carbon released. Owing to its great movability, the carbon which is released in the lattice has a tendency towards effusion during a heat treatment. The decarbonisation which takes place depending on the C-potential of the gas phase, under which the heat treatment takes place, with or without simultaneous scaling, therefore represents one of the oldest problems in the production and processing of steel.
In principle, a decarbonisation is carried out in accordance with the Boudouard equilibrium reactions in accordance with the following reaction processes:[C]+½O2<->CO[C]+O2<->CO2 [C]+CO2<->2CO[C]+H2<->CH4 where [C]=carbon released
In commercial annealing installations having a typical protective gas atmosphere which contains hydrogen, nitrogen and water vapour, the following equilibrium reaction is produced:H2+½O2<->H2O
Gas atmospheres containing water have been found to be particularly reactive with respect to carbon. Therefore, an additional heterogeneous equilibrium reaction which is particularly significant in practice supplements the decarbonisation reactions mentioned:[C]+H2O<->CO+H2
When used in a selective manner, properties of a steel product determined by means of a decarbonisation can be improved.
In order to be able to use this knowledge effectively in practice, the "Open Coil" method is proposed in GB 1 189 464. In this method, a hard-rolled, cold-rolled strip is wound so loosely to form a coil that a free space is provided in each case between the individual winding layers of the coil. The annealing gas which flows through the free spaces during the subsequent annealing treatment in a hood type furnace then flows over the entire steel surface in a uniform manner so that a uniform decarbonisation result is achieved over the entire length of the processed steel strip. However, the annealing treatment which is carried out in this manner takes several hours.
A method which can be carried out more economically for decarbonisation annealing of steel strip in a continuous furnace under a reducing annealing atmosphere is described in DE-OS 2 105 218. According to this known method, the respective steel strip is annealed at an annealing temperature of less than 780° C. over a sufficiently long annealing period until the carbon content in the steel strip is less than 0.01% when leaving the continuous furnace. Subsequently, the steel strip can be provided with a hot-dip coating in order to improve its corrosion resistance. The sheet steel which is produced in this manner has particularly good formability. However, its strength values do not meet the demands which are regularly placed nowadays on flat steel products, from which components for motor vehicle bodywork are intended to be formed.
A suggestion known from WO 2009/024472 A1 also referred to the "Open Coil" method according to which there has been proposed, for a steel strip which comprises a tool steel and which is intended in particular for the production of cutting tools and the like and which has a C content of at least 0.4% by weight, a decarbonisation of the edge layer in order to combine a high level of hardness with good formability. In the region of the decarbonised edge layer, the steel strip which is processed accordingly has increased formability with respect to the base material, whereby the danger of brittle fracture with high external load is reduced.
In contrast to the applications considered in WO 2009/024472 A1, the person skilled in the art, with high-strength and extremely high-strength steels which are intended for the production of high-strength components, generally seeks to avoid, if possible, the decarbonisation or edge decarbonisation which is caused by annealing. It is generally considered that the decarbonisation has a negative influence on the mechanical material properties which are important for these applications.
Following this notion, there has been proposed in DE 102007061489 A1 a method wherein a ductile edge layer which is advantageous for forming is produced on a steel sheet by carrying out selective oxidation of the hardening alloy elements. Any decarbonisation is selectively counteracted in this instance.

Method for producing a flat steel product which can be readily formed, flat steel product and method for producing a component from such a flat steel product


An asphalt pavement remover includes a rectangular backplate for attachment to moving equipment, an L-shaped lifting blade attached to the front of the backplate and a wedge-shaped splitter attached to the L-shaped blade. The L-shaped blade includes an upstanding arm and a lower arm, the latter of which is similar to a fork-lift blade. The wedge-shaped splitter extends in the direction of the lower arm of the L-shaped blade, i.e., away from the upstanding arm. The splitter has a forward wedge-shaped edge which is located rearward of the forward end of the lifting blade.

1. Field of the Invention
This invention relates broadly to an apparatus for cutting up and dislodging asphalt pavement so that it can be removed with minimal disturbance to the subgrade, and, optionally, replaced. More particularly, this invention relates to an attachment for a skid steer, bucket loader, tractor or the like which is then used to cut and dislodge asphalt pavement
2. State of the Art
Asphalt is one of the most popular materials for paving roads, driveways, and parking lots. There are many reasons why asphalt pavement may need to be removed and replaced. One reason is to access something buried beneath it such as a cable or a fluid conduit. Another reason is normal maintenance. Over the course of time asphalt pavement deteriorates to the point where it must be removed and replaced.
It has been known for some time to attach an asphalt pavement cutting device to moving equipment such as a tractor, backhoe, or forklift. U.S. Pat. No. 3,885,833 to Lemieux discloses a cutter attachment which is adapted to be installed on the forward edge of a bucket of an earth moving vehicle. The attachment includes an elongated blade support body with a rear horizontal slot for receiving the forward lower edge of the bucket and a forward end or nose. The attachment further includes a pair of generally rectangular and flat, co-planar, vertically extending fins mounted centrally on the cutter body. This attachment is intended for cutting the surface of blacktop. The fins extend upward and downward respectively. However, only the downward extending fin is actually used to cut.
U.S. Pat. No. 4,043,601 to Schiller discloses an asphalt cutter having a flat-sided lifter blade with inner edges and a pair of flat co-planar "keepers" on each side of the blade. The asphalt cutter is attached to a tractor-like machine equipped with an adjustable header, bucket or draw bar.
U.S. Pat. No. 4,749,048 to Kelly discloses a ripper attachment for a skid steer loader having a triangular frame, a mounting plate attached at the base of the triangular frame, and a scarifier receptacle attached at the apex of the triangular frame. A single shank scarifier is fastened to the apex and is oriented downward so that the tooth is drivable into the ground for ripping purposes.
All of the known asphalt pavement cutter attachments have some disadvantages. In general, it would be desirable to provide an attachment for a skid steer, bucket loader or the like which overcomes all of the disadvantages of the prior art devices.


A heat dissipation module with twin centrifugal fans is described. The heat dissipation module is utilized in an electrical equipment and especially for a computer server system. The heat dissipation module has a honeycomb panel, a first fan, an air duct, a second fan and a plurality of sliding rails. The honeycomb panel connects with an outlet of the first fan and an out of the air duct in the rear side thereof. The first fan sucks hot air from the underside thereof and exhausts the hot air to the outside through the honeycomb panel. The second fan sucks hot air from the underside thereof and exhausts the hot air to the outside through the honeycomb by way of the air duct. The sliding rails configure along the two sides of the first fan and the second fan.

Due to the rapid progress of the computer industry, information technology is highly developed now. Additionally, network applications are full of vitality so that a great quantity of data transmission and calculation are transmitted by networks. Therefore, more computer equipment is provided for data calculation and process by way of network connections.
Because the functional requirements of the semiconductor are highly intense, the electric circuit layout of the semiconductor is more complicated and more sophisticated. The computer equipment is increasingly powerful. Powerful computer equipment with complicated and sophisticated semiconductors induces a serious problem. That is, a complicated and sophisticated semiconductor has a higher power consumption and thus severely elevates the working temperature of the computer equipment.
Normally, a higher working temperature can cause instability in a working system, and especially in computer equipment. A lower working temperature makes a computer equipment more stable. That is to say, if the working temperature of the computer equipment can be kept lower, the performance thereof is higher. Nevertheless, if the working temperature is too high, the performance and stability will decrease and the operation system may even crash, in some extreme situations.
Therefore, a heat dissipation device is very important for the computer equipment and especially to a computer server system. Because a computer server system works continuously, the heat accumulation is more severe than in normal computer equipment, e.g. a personal computer. Additionally, a computer server system normally possesses more than one computer server installed in a rack. Accordingly, the heat dissipation device of the computer server system is more serious and important.

Heat dissipation module with twin centrifugal fans


A method is disclosed for forming an ultrathin oxide layer of uniform thickness. The method is particularly advantageous for producing uniformly thin interfacial oxides beneath materials of high dielectric permittivity, or uniformly thin passivation oxides. Hydrofluoric (HF) etching of a silicon surface, for example, is followed by termination of the silicon surface with ligands larger than H or F, particularly hydroxyl, alkoxy or carboxylic tails. The substrate is oxidized with the surface termination in place. The surface termination and relatively low temperatures moderate the rate of oxidation, such that a controllable thickness of oxide is formed. In some embodiments, the ligand termination is replaced with OH prior to further deposition. The deposition preferably includes alternating, self-limiting chemistries in an atomic layer deposition process, though any other suitable deposition process can be used. Two or more of the HF etching, surface termination, oxidation, hydroxyl replacement of the surface termination and deposition on the oxide can be conducted in situ.

The invention relates generally to integrated circuit fabrication, and more particularly to providing an ultra-thin oxide layer of uniform thickness over semiconductor structures.
Thin oxide layers are often desired over semiconductor surfaces in fabricating integrated circuits. For example, silicon oxide for conventional gate dielectrics for integrated transistors are typically grown on a single crystal silicon wafer or epitaxial silicon layer. Even for alternative gate dielectric materials, very thin silicon oxide layers are typically grown first for superior silicon/oxide interface characteristics. Similarly, silicon oxide is often grown on silicon electrodes in capacitors for memory cells, such as in dynamic random access memory (DRAM) arrays.
Prior to thermally growing silicon oxide, the silicon surface is desirably cleaned to avoid contamination and produce superior electrical properties. Among other things, the surface is generally cleaned of a naturally forming oxide known as xe2x80x9cnative oxide.xe2x80x9d
As is well known in the art, native oxide forms naturally over bare silicon surfaces even upon exposure to clean room environments at room temperature. Typically, native oxide comprises a few angstroms of silicon oxide, a substantial portion of the dielectric film to be formed. While a thermal oxide can be grown through the native oxide to complete the desired dielectric layer, the quality and thickness of the native oxide are inconsistent across the silicon surface. Moreover, the native oxide left after long transportation and/or storage is typically contaminated with impurities.
Accordingly, native oxide is typically removed from the surface with solutions such as dilute hydrofluoric acid (HF) baths or HF vapor etching. Dipping the wafers in a dilute HF bath cleans the silicon surface native oxide and leaves the surface hydrogen terminated. HF vapor etching similarly cleans the silicon surface and terminates dangling silicon bonds, but the surface termination includes a substantial fluorine content. Hydrogen termination is not very stable, particularly at elevated temperatures. The hydrogen atoms readily desorb to leave the dangling silicon bonds that tend to attract atmospheric contaminants. Even with hydrogen and fluorine termination in place, atmospheric oxidants can still diffuse through the termination layer between HF treatment and subsequent processing. Thus, HF treatment cleans the wafer surface but leaves the surface inadequately protected for the period between cleaning and further processing. The composition of this regrown oxide strongly depends on many different conditions, such as the doping levels within the silicon and concentration of moisture within the air, such that this oxide regrowth is also inconsistent and difficult to control.
One manner in which a clean silicon surface can be maintained for longer periods of time is to quickly grow a thin silicon oxide passivation layer after cleaning the silicon surface. Such a passivation layer can also be used to provide improved interface characteristics between a silicon structure and more advanced dielectric materials, such as those exhibiting high dielectric permittivity (high-k dielectrics). Spontaneous oxide regrowth, such as by room temperature exposure to typical oxidants like air or water, results in a very slow reaction, which is unacceptable for commercial fabrication. Studies show that oxide regrowth after HF treatment, sufficient to provide a thin silicon oxide passivation layer, can take on the order of 103 to 104 minutes.
As is well known, this oxidation rate can be increased by heating the wafer during oxidation. Unfortunately, thermal oxidation at temperatures greater than 500xc2x0 C. causes the hydrogen termination left by HF treatment to desorb well before temperatures reach the level at which significant oxidation takes place. In the interim, the silicon surface is left unprotected. Moreover, thermal oxidation of the initially bare silicon substrate proceeds rapidly and by mechanisms that are not well understood, as compared to latter stages during which oxidants diffuse through an already-grown portion of the silicon oxide. Accordingly, when attempting to provide oxide thicknesses appropriate for passivation and interface improvement beneath high-k materials, the oxidation is not easily controlled and can easily exceed the desired thickness.
Oxidation can be more easily controlled using room temperature wet oxidation by immersion in water. Dissolving ozone in water can improve the oxidation rate relative to water alone. Moreover, concentration of the dissolved ozone can be controlled to tailor the growth rates. Unfortunately, wet processing is not compatible with rapid sequential processing steps. Wet processing stations are typically separated from cluster tools, as moisture can be corrosive to vapor processing tools like chemical vapor deposition (CVD) reactors and vapor etching tools.
Accordingly, there is a need for improved methods for providing passivation layers over silicon surfaces. Such methods should desirably be finely controllable for tailoring passivation layer thicknesses between about 0.1 nm and 1.2 nm.
The preferred embodiments present methods of growing extremely fine oxide layers in a controllable fashion. In particular, the rapid growth of thermal oxidation is tempered by forcing such oxidation to take place through a protective layer of surface termination or ligands.
In the illustrated embodiments, termination of silicon surfaces left by HF vapor or wet etching (which cleans native oxide from a silicon surface) is replaced by oxidation-moderating or -inhibiting ligands. The ligands can comprise OH formed from exposure of the clean silicon to water (H2O). In another embodiment, the ligands comprise more effective oxidation-moderating species. For example, such oxidation-moderating termination can be formed by exposing the clean silicon to compounds capable of forming alkoxides, such as alcohols, or to carboxylic acids.
Oxidation is then conducted through the surface termination. Temperatures for this process are preferably maintained between about room temperature (25xc2x0 C.) and 400xc2x0 C. Preferably, the oxide grown through the surface termination comprises between about 0.1 nm and 1.2 nm, formed uniformly across the silicon surface. Following oxidation, the surface termination is replaced, if necessary, with OH termination, which advantageously facilitates deposition of a further dielectric layer upon the oxide. Further deposition can be by chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD) or any other film deposition method known in the art. Most preferably, the further dielectric layer is characterized by a high permittivity constant (e.g., greater than about 10).
Advantageously, the methods can be implement with two or more sequential steps conducted in situ, i.e., without removing the workpiece from a reaction chamber between steps.
An exemplary context for the invention is the formation of a uniform gate dielectric, incorporating a high k dielectric with an interfacial oxide over a semiconductor substrate, for use in a transistor gate stack.


Aspects of the present invention are directed to a propeller protector that can accommodate propeller of different sizes and is designed to be easily installed or removed from a propeller. The propeller protector includes a novel retaining device for securing the protector onto the blades of the propeller without using straps or similar devices. The novel retaining device has a high level of adaptability to accommodate blades of different sizes and shapes.

Aspects of the present invention relate to propeller protectors, and more particularly, a propeller protector of inboard or outboard marine motor to improve safety to persons or animals in close proximity of a propeller. The blades of the propeller generally have sharp edges that can be hazardous to people or animals that come into contact with the blades. Severe injury is likely when accident occurs with an unprotected propeller.
Marine vessel or watercrafts operators often maneuver or anchor in relatively shallow water in various boating activities such as swimming, fishing, diving, snorkeling, etc. In these activities, the passengers often participate in activities in close proximity of the propeller. While the propeller may be stopped during these activities, its sharp unprotected blades can severely injury any person who may accidentally come into contact with the blades. Furthermore, underwater visibility may not be ideal, thus hindering the ability of the people above or in the water to see the propeller. It is also possible that strong current may be present in the water, and the people in the water may be pushed toward the propeller unknowingly.
Various safety devices have been used to protect a propeller in or out of the water. For example, the propeller may be encased in a cage that allows the propeller to be operated with the cage attached. However, such protective cage may create undesirable drag in the water and reduce the efficiency of the motor. The cage may also decrease the maneuverability of the boat in shallow water.
Various protective covers have been used to cover the propeller. Some covers include individual covers for each blade of the propeller. However, the individual covers may easily be lost or misplaced. Some covers include a box shape enclosure that is sized to cover all the blades. However, known examples of these type of covers generally use some forms of attachment devices or straps to secure or attach the cover to the propeller shaft, or to have an opening that is sized to be smaller than the propeller's size. While some protectors may be adjustable to accommodate different propeller sizes, the adjustment operation is often cumbersome and time consuming in order to install or remove the propeller cover. Therefore, there is still a need for a propeller protector that can be used on propeller of different sizes and can be easily installed and removed while the propeller is submerged, for example, when a boat remains stationary with its engine off in the water or being loaded into the water from a trailer.


A pattern searching method using neural networks and correlation. This method combines the quickness and adaptiveness of neural networks with the accuracy of the mathematical correlation approach. Images are divided into small sub-images which are presented to the trained neural network. Sub-images that may contain the pattern or partial pattern are selected by the neural network. The neural network also provides the approximate location of the pattern, therefore the selected sub-images can be adjusted to contain the complete pattern. Desired patterns can be located by measuring the new sub-images' correlation values against the reference models in a small area. Experiments show that this superior method is able to find the desired patterns. Moreover, this method is much faster than traditional pattern searching methods which use only correlation.

1. Field of the Invention
This invention relates generally to the field of pattern searching and recognition. More particularly, this invention relates to use of a combination of neural networks with correlation techniques to quickly and accurately recognize patterns with reduced computational complexity.
2. Background of the Invention
Pattern Searching is one of the most extensively used functions in industrial image systems. Applications for pattern searching can be generally divided into three categories: alignment, gauging, and inspection. Conventional pattern searching basically involves two steps of operations. First comes the problem of locating one or more regions of interest in a larger image, then isolating the patterns in the regions of interest for the next step of the process. For example, in circuit board alignment applications, the second step is to find the exact locations of the pre-defined fiducial marks and then align the circuit board to a reference based on the positions of those found fiducial marks.
In the past few years, neural networks have been quite successfully applied to many pattern recognition and vision problems. Several such applications are described in Fukushima, K., "Neocognition: A hierarchical neural network capable of visual pattern recognition," Neural Networks 1, 119-130, 1988; Rumelhart D. E., Hinton, G. E., and Williams, R. J., "Leaning internal representation by back-propagating errors," Nature, 323:533-536, 1989; and LeCunn, Y. and et al, "Backpropagation Applied to Handwritten Zip Code Recognition," Neural Computation 1, 541-551, 1989. However, most of the applications in these areas have been using binary images, for example character recognition. To accurately locate patterns, in general, gray-level images are required. Due to the variations in brightness in gray-level images, it is difficult to train neural networks to accurately locate patterns in different lighting conditions.
On the other hand, the correlation method which measures the geometric similarity between an image and reference models has been widely used in many industrial image systems. One of the most important properties in correlation is that correlation is independent of uniform linear changes in brightness in either the models and images. However, correlation itself is a very computationally expensive operation. Moreover, to search patterns, correlation has to be applied to all possible locations in the regions that may contain the patterns. For example, to search an 8.times.8 pattern in a 16.times.16 image, 81 correlations are required to find the best correlation between the pattern and model. Therefore, special hardware is usually required as described in "Technical Description: Vision for Industry", Cognex Corporation, 1990.
The present invention seeks to ameliorate some of these problems by using the speed of neural network techniques to complement the accuracy and grey scale handling abilities of correlation techniques.

Pattern searching method using neural networks and correlation


A device generating a drawing to be output determines a scale of the drawing based on a size of an output area and generates a drawing to be output based on the determined scale. In this way, a drawing with an appropriate scale can be generated.

1. Technical Field
The present disclosure relates to a device, a method, and a recording medium for generating a drawing to be output.
2. Description of the Related Art
It has conventionally been known that a computer such as a personal computer (PC) displays a map on a display screen, based on map data stored in a memory. Japanese Patent No. 3494920 discusses displaying a map stored in a memory in a PC or in a server on a network, on a display screen.
However, when a drawing such as a map is output in a case of the above conventional technique, the drawing may not be output with a scale appropriate for the size of an output target area.
For example, if a printing device prints a large-scale map including detailed information on a small print medium, the detailed information about geographical names, building names, etc. included in the map is printed in small sizes. Thus, when viewing the map on the print medium, the user may not grasp such detailed information. In addition, since the detailed information is printed on a small print medium, the user may find it actually difficult to view necessary information about streets, etc. In an opposite manner, a small-scale map including general information may be printed on a large print medium. In such case, while the map has been printed on a large print medium, detailed information about geographical names, etc. may not be printed.

Device, method, and recording medium for outputting image


An information searching apparatus and method capable of producing good search results even in the case where specified search keywords are found separately on a plurality of documents. Upon receipt of a search request from a client, a first search process searches an index memory to find tentative search results. According to predetermined rules, it is determined to which group each tentative search result should belong. A second search process then searches documents at an upper hierarchical level in the same group, thus finding keyword hits in an upper-level document. A higher priority is then given to a group of documents in which the second search process has found keyword hits. Finally a list of locators is compiled and sent back to the requesting client to indicate the locations of relevant documents, where the locators are arranged in descending order of the display priority of corresponding groups.

1. Field of the Invention
The present invention relates to an apparatus and method for information search, and more particularly to an information searching apparatus and method that search documents arranged in a hierarchical structure.
2. Description of the Related Art
Information search services play an essential role in effective use of a large amount of documents on the Internet and other networks. Application programs for web search service are therefore installed in servers for portal sites or the like. Such web search applications run on a server to provide search engine capabilities that enable users to search online resources easily.
Some search engines employ a program called "robot" that continuously crawls through the network to collect document information. This type of search engines extract keywords from collected documents to construct a database, known as an "index," containing a list of extracted keywords associated with the individual documents. When a search request is received from a client, the search engine consults the index files to find records that match with the search keywords specified in the request. If relevant records are found, the search engine sends search results back to the client, including uniform resource locators (URLs) of the found documents.
Public information available on a website is not necessarily concentrated in a single location. Rather, it is often divided in a plurality of documents written in the hypertext markup language (HTML) format, for example. Conventional search engines perform a search on individual HTML files in a website.
FIG. 24 shows an example of a conventional search technique. It is assumed in FIG. 24 that an index memory 91 of a search engine 92 contains three sets of indexes 91a, 91b, and 91c created previously for three documents that are accessible by their respective URLs, "A.html," "B.html," and "C.html" (domain name is omitted for simplicity). Those documents are available on a website of a company named "FTSU Limited" (which is a fictitious name for explanatory purposes). Note that A.html includes the term "FTSU," and C.html includes the term "officers."
Suppose now that a user has sent a search string "FTSU and officers" to the search engine 92 in an attempt to find a list of corporate officers of FTSU Limited. The reserved word "and" in this search string serves as a logical AND operator, which commands the search engine 92 to retrieve documents containing both search keywords, "FTSU" and "officers," by consulting the indexes 91a, 91b, and 91c. In other words, the search engine 92 will not pick up those documents unless they contain every specified keyword. Because of this restricted search condition, no match is found on the website of FTSU Limited in the present example.
While the documents like A.html and C.html may have originally been a single document, they are actually stored as separate files because of some managerial needs in the website system operations. As a consequence, an AND search ends up with no hits, failing to provide the user with the needed information. The AND search would be successful if the two documents were indexed as a single combined document on the search site. However, combining multiple documents often results in a too large file for a search engine to handle efficiently. The users would therefore experience slow responses in searching and displaying documents. For this reason, combining documents is not a practical approach.
To seek more documents related to the topic, the users may use an OR search, instead of an AND search, instructing the search engine to find documents containing "FTSU Limited" or "officers" or both. However, the search results of this OR search are likely to include a large number of irrelevant hits.
Refining, or narrowing down, search results is then expected to be a better approach to achieve good outcomes. One technique for refining search results is to restrict the search. A domain search allows a user to designate a specific website domain for searching. If a domain name is specified, the search engine searches documents only within that domain. If, in the present example, the user knows the domain name of a website of FTSU Limited, he/she can specify that site as a search domain in seeking documents with a search keyword "officers." By doing so the user can reach C.html, which is a desired search result. This type of domain search technique is used by Google.
The above-described domain search technique, of course, is only useful in the case the target domain name is known. Many of the novice search site users, however, do not know such refining techniques. They have to repeat search sessions, adding and changing search keywords, until they can reach the desired information. The search, however, would only be successful if the document includes all specified search keywords.
While it would be also possible to add keywords for each site, doing this for every site on the Internet requires an enormous amount of workload. This would impose excessive administrative burdens on the operating company of a search engine.

Information searching apparatus and method with mechanism of refining search results


A particulate mass monitor includes two mass sensors, such as an optical sensor (e.g., a light scattering photometer or nephelometer) and a beta radiation attenuation sensor for substantially continuous monitoring of ambient particulate matter. During operation, the first mass sensor references the time-averaged measurement of the second mass sensor such that the second mass sensor calibrates the response of the first mass sensor. If the first sensor is an optical sensor, as it detects the presence of particulate matter within a fluid, the mass concentration measurement (e.g., signal output) provided by the optical sensor is altered using a ratio of concentration measurements of the second mass sensor and the optical sensor. The combined use of the two mass sensors provides accurate mass measurements of ambient particulate matter with a relatively high time resolution.

Ambient air quality affects the health of people breathing the ambient air. The lower the air quality, the greater the risk for health-related problems induced by the ambient air. Conventional particulate matter monitoring devices measure the mass concentration of particulate matter within ambient air, gases, or other fluids to determine quality of the ambient air or gaseous fluid. A conventional particulate matter monitoring device can provide a warning to a user when the device detects a relatively low air quality (e.g., a relatively large particulate mass concentration within the air) or a decrease in the ambient air quality based upon an increase in particulate mass concentration measured over a specific time period.
Several sensing techniques provide continuous direct monitoring of airborne particulate mass concentration. The sensing techniques used for particulate monitoring include, for example, mass sensing methods such as beta radiation attenuation and optical sensing methods such as light scattering photometry or nephelometry.
Beta radiation attenuation devices typically include a mass sensing stage and a particle collection stage. The mass sensing stage includes a beta particle radiation source, typically carbon-14 or krypton-85, and a beta radiation detector, typically a Geiger-Muller detector, plastic scintillator, a proportional counter, or an ionization chamber. The particle collection stage includes a filter oriented between the beta radiation source and the beta radiation detector. Beta radiation attenuation devices exhibit a substantially exponential attenuation characteristic as a function of the mass per unit area collected by the filter between the radiation source and the radiation detector. For example, during operation, ambient air (or another gaseous compound) flows through the filter and the filter collects particulate matter present within the ambient air over time. As the amount of particulate matter collected by the filter increases, the particulate matter attenuates the beta radiation emitted from the radiation source (i.e., the beta radiation detector senses less radiation from the beta source) as detected by the detector. Because the attenuation of the beta radiation detected by the beta detector is related to the mass of the particulate matter collected by the filter (e.g., and does not substantially depend upon the type or compound of material collected by the filter), a beta radiation signal produced by the beta radiation attenuation device indicates a mass concentration of particulate matter within an air sample.
Beta radiation attenuation devices, and other mass sensing devices that utilize a filter to collect particulate matter within an air sample, sometimes utilize temperature and humidity conditioning elements to remove liquid water from the air sample. Typically, air samples include varying amounts of water and water vapor. If the filter collects water over time, the water adds to the attenuation of the beta radiation from the beta radiation source to the beta detector. The water that collects in the filter, therefore, can affect the accuracy of the device's detection of mass of particulate matter within the air sample. In conventional beta radiation attenuation devices, prior to the air sample reaching the filter, the device heats the air sample to ensure that the water in the air and on the particulate matter evaporate from the air sample. By keeping the water within the air sample as a vapor instead of condensation, the temperature and humidity conditioning elements can increase the particulate matter detection accuracy of the device by reducing or eliminating collection of water in the filter.
Another type of conventional particulate mass sensing device is a light scattering device known as a nephelometer. Light scattering photometry devices, such as nephelometers, measure the irradiance of light scattered by particles passing through a sensing volume. Typical light scattering photometry devices include a light source that creates an illuminating light beam and detection optics or sensors that measure the strength of the scattered light. During operation, ambient air or another gas flows through a sensing volume defined by an intersection of the illuminating beam and the field of view of the sensing optics. As the air flows through the sensing volume, the light source illuminates particles present within the sensing volume, and the optics and associated photosensitive measuring circuitry detect the light scattered by the particles. For an ambient air sample having a fixed size distribution of particles with invariant density and index of refraction, the intensity of light scattered by the particles within the air sample is directly proportional to the mass concentration of the particles within the air sample. Light scattering photometry or nephelometry devices, therefore, allow real-time (i.e., substantially instant) measurement of particulate mass concentration of ambient air.

Methods and apparatus for monitoring a mass concentration of particulate matter