Optical dispersion imposed on a communications signal conveyed through an optical communications system is compensated by modulating the communications signal in the electrical domain. A compensation function is determined that substantially mitigates the chromatic dispersion. The communications signal is then modulated in the electrical domain using the compensation function. Electrical domain compensation can be implemented in either the transmitter or the receiver end of the communications system. In preferred embodiments, compensation is implemented in the transmitter, using a look-up-table and digital-to-analog converter to generate an electrical predistorted signal. The electrical predistorted signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical communications system.

Optical communications systems typically include a pair of network nodes connected by an optical waveguide (i.e., fiber) link. Within each network node, communications signals are converted into electrical signals for signal regeneration and/or routing, and converted into optical signals for transmission through an optical link to another node. The optical link between the network nodes is typically made up of multiple concatenated optical components, including one or more (and possibly 20 or more) optical fiber spans (e.g., of 40-150 km in length) interconnected by optical amplifiers.
The use of concatenated optical components within a link enables improved signal reach (that is, the distance that an optical signal can be conveyed before being reconverted into electrical form for regeneration). Thus, for example, optical signals are progressively attenuated as they propagate through a span, and amplified by an optical amplifier (e.g., an Erbium Doped Fiber Amplifier—EDFA) prior to being launched into the next span. However, signal degradation due to noise and dispersion effects increase as the signal propagates through the fiber. Consequently, noise and dispersion degradation become significant limiting factors of the maximum possible signal reach.
Dispersion, also known as Group Velocity Dispersion or Chromatic Dispersion, in single mode fibre at least, occurs as a result of two mechanisms:                a) Waveguide dispersion—within a single mode fibre, different wavelengths travel along the fibre at different speeds; and        b) Material dispersion—the phase velocity of plane waves in glass varies with wavelength.
For the purposes of the present invention, references to "dispersion" shall be understood to mean the sum total of group velocity dispersion effects.
Mathematically, first order dispersion is the derivative of the time delay of the optical path with respect to wavelength. The effect of dispersion is measured in picoseconds arrival time spread per nanometre 'line width' per kilometre length (ps nm−1 km−1). The magnitude of waveguide and material dispersions both vary with wavelength, and at some wavelengths the two effects act in opposite senses. The amount of dispersion present in a link can also vary with the temperature of the cable, and if the route is changed (e.g., using optical switches). Dispersion in optical fibre presents serious problems when using light sources whose spectrum is non-ideal, for example broad or multispectral-line, or when high data rates are required, e.g., over 2 GB/s.
For the purposes of analyzing the effects of dispersion, it is convenient to represent an optical communications system using the block diagram of FIG. 1. In this case, the transmitter is represented by an electrical-to-optical converter (E/O) 2 which operates to convert an electrical input signal x(t) into a corresponding optical signal XOPT(w) for transmission to the receiver. The optical fiber span 4, including all concatenated components, is represented by a transfer function H(w), which will normally be complex. The Receiver is represented by an optical-to-electrical converter (O/E) 6 which detects the optical signal YOPT(w) received through the optical fiber span 4, and generates a corresponding output signal y(t). For a linear optical channel, the received optical signal YOPT(w) will nominally be equivalent to the product of XOPT(w) and H(w).
In general, the output signal y(t) represents a distorted version of the input data signal x(t). While it would be highly desirable for H(w)≈1, this is rarely the case. Accordingly, it is frequently necessary to utilize at least some form of compensation, so that the original input data signal x(t) can be detected within the distorted output signal y(t).
One commonly used method of addressing the problem of dispersion in high-bandwidth communications systems is by inserting one or more optical dispersion compensators 8, represented in FIG. 1b by the compensation function C(w), within the link. Such dispersion compensators may, for example, take the form of length of fibre, a Mach Zehnder interferometer, an optical resonator, or a Bragg reflector. Some of these compensators can also produce a controllable amount of compensation, which enables mitigation of time-variant dispersion effects. In either case, these compensators are intended to at least partially offset the signal distortions introduced by the system transfer function H(w). The compensation function C(w) is a dispersive function that is selected to optimize performance of the link. In a fully linear system, the compensation function C(w) would preferably be equivalent to the complex conjugate H*(w) of the transfer function H(w), in which case H(w)*C(w)=1, and the combined effect of H(w) and C(w)=H*(w) would be an undistorted received signal YOPT(w) that exactly corresponds to the original optical signal XOPT(w). However, limitations of optical components, and the time-varying amount of compensation required, make this objective very difficult to achieve. Additionally, optical compensators are expensive and introduce significant optical losses. These losses must be offset by means of additional optical gain which introduces more optical noise. The additional (or higher-performance) optical amplifiers required to provide this increased gain further increases the total cost of the communications system. In addition, the presence of optical dispersion compensators and high performance amplifiers distributed along the length of the link provides a significant technical barrier to system evolution. For example, implementation of optical switching (e.g. at the Tx and/or Rx ends of the link, or an intermediate site without electrical termination) necessarily requires adjustment of optical amplifiers, in order to accommodate changing energy states within the link.
These problems can be alleviated by moving the compensation function to the terminal ends (e.g., the transmitter 2 and/or receiver 6) of the link. This technique typically involves "preprocessing" the input signal x(t) at the transmitter (Tx) end of the link 4 to improve dispersion tolerance, and/or processing the output signal y(t) detected at the receiver (Rx) end of the link to accurately detect the input signal x(t) within the distorted output signal y(t).
For example, high bandwidth traffic can be distributed over a larger number of lower-rate channels. The reduced bit-rate of each channel enhances the dispersion tolerance in proportion to the square of the reduction in the bit-rate. However, this approach is expensive, spectrally inefficient, and creates four wave mixing problems.
Dispersion tolerance can be increased by narrowing the spectrum of the transmitted optical signal. Various known techniques may be used for this purpose, such as multilevel coding. However, this requires expensive electronics and significantly reduces the noise tolerance of the communications system.
Subcarrier multiplexing, which involves transmitting a plurality of lower bit-rate signals over one optical carrier, is another known method of increasing dispersion tolerance. In this case, the dispersion tolerance obtained is equivalent to that of the lower bit-rate subcarrier. However this approach is not cost effective and does not have a good noise tolerance.
The optical spectrum occupied by a signal can be reduced by use of modulators with reduced chirp, such as a Mach-Zehnder modulator. The amount of chirp can even be tailored to optimize transmission over a particular moderate amount of dispersion. One variation of this technique is referred to as dispersion supported transmission, an example of which is discussed in EP-A-0643 497. In this case, dispersion produces an FM to AM conversion effect, which can facilitate bit detection and thereby extend transmission distance without controlling or compensating dispersion. The dispersion causes shifting of adjacent signal components of different wavelengths, resulting in either energy voids or energy overlaps at the bit transitions. Constructive interference in an overlap causes a positive peak in the optical signal, while a void produces a negative peak. In principle, these positive and negative peaks represent an AM signal which may be detected to reproduce the original bit stream. This has proved difficult to implement over a reasonable range of practical link dispersions.
Many transmission formats are known that enable somewhat increased dispersion tolerance, for example, as described in U.S. Pat. No. 5,892,858. However none of these formats provide sufficient dispersion tolerance to allow a wide bandwidth signal to be accurately detected in the presence of large amounts of dispersion.
It is known that the use of a coherent receiver enables the signal degradation due to dispersion to be removed via linear electrical filtering. However, because of their high cost, very few coherent optical receivers have been installed, and the cost of replacing installed receivers with the high-performance coherent receivers is prohibitive.
The majority of receivers installed in modern optical communications networks are of the direct detection type. Due to the well known squaring effect in these receivers, electrical processing of the output signal y(t) is capable of compensating only a very limited amount of dispersion. See, for example, "Performance of Smart Lightwave Receivers with Linear Equalization" Cartledge et al, J Lightwave Tech, Vol. 10, No. 8, August 1992, pp.1105-1109; and "Electrical Signal Processing Techniques in Long-Haul Fiber-Optic Systems" Winters et al, IEEE Trans. Comms, Vol. 38, No. 9, September 1990, pp. 1439-1453}.
In addition to the squaring effect in conventional receivers, optical modulators also frequently display a non-linear performance characteristic. Nonlinearity compensation of modulators can be implemented in the electrical domain ("Reduction of Dispersion-Induced Distortion in SCM Transmission Systems by using Predistortion-Linearized MQW-EA Modulators", Iwai et al, J. Lightwave Tech., Vol. 15, No. 2, February 1997, pp. 169-177). It is also possible to provide the nonlinear compensation in the optical domain ("Mitigation of Dispersion-Induced Effects using SOA in Analog Optical Transmission", Jeon et al, IEEE Photonics Technology Letters, Vol. 14, No 8, August 2002, pp. 1166-1168 and "Predistortion Techniques for Linearization of External Modulators", Wilson, 1999 Digest of the LEOS Summer Topical Meetings, 1999, pp. IV39-IV40), or via hybrid optical/electrical domains ("Signal Distortion and Noise in AM-SCM Transmission Systems employing the Feedforward Linearized MQW-EA External Modulator", Iwai et al, J. Lightwave Tech., Vol. 13, No. 8, August 1995, pp. 1606-1612 and U.S. Pat. No. 5,148,503.
While modulator non-linearity can be compensated, the output signal y(t) detected at the Rx end of the communications system contains distortion components due to non-linearities in both the modulator (transmitter) 2 and the receiver 6, as well due to optical dispersion within the link 4. These distortions are compounded, one upon the other, and it is difficult to distinguish distortions of the output signal y(t) due to non-linearity of the modulator 2 or the receiver 6. It is also difficult to distinguish these effects from dispersion.
Accordingly, a cost-effective technique for mitigating the effects of dispersion on high bandwidth optical signals remains highly desirable.

Electrical domain compensation of optical dispersion in an optical communications system


Reversibility in the directivity in the event of transmission/reception through a multi-antenna system is well suitably compensated for by executing self-calibration. A branch is set to a reference branch, and a forward loopback transfer function and a backward loopback transfer function are acquired, whereby per-branch calibration factors are calculated. Subsequently, an other branch is set to a reference branch, and calibration factors are calculated in a similar manner. Then, the calibration factor for the reference branch is corrected in accordance with the secondly obtained calibration factor so that a calibration condition is satisfied.

As apparatuses to be relieved from wirelines in conventional wired communication apparatus, wireless networks have been drawing attention. Among standard specifications related to wireless networks, IEEE (The Institute of Electrical and Electronics Engineers) 802.11, for example, is known.
For example, as a standard specification regarding wireless LANs, in IEEE 802.11a/g there is employed an OFDM (Orthogonal Frequency Division Multiplexing) modulation scheme, which is one of multicarrier scheme. According to the OFDM modulation scheme, because transmission data is transmitted by being distributed to a plurality of carriers set with frequencies perpendicular to one another. As such, the band of the respective carrier is narrow, in which case the frequency utilization efficiency is very high, and the resistance against frequency selectivity phasing disturbance is high.
Further, according to the IEEE 802.11a standard, although a modulation scheme capable of achieving a communication speed of 54 Mbps at maximum is supported, a wireless communication standard enabling the accomplishment of even higher bit rates is demanded. Wireless communication techniques enabling high-throughput wireless data transmission include a multi-antenna system in which a communication apparatus includes multiple antennas.
An adaptive array antenna is widely known as one example of multi-antenna techniques. According to the technique, the gains of respective antenna elements are controlled, and appropriate transmission and reception antenna directivities are acquired, thereby to support communications. More specifically, appropriate weight coefficients are multiplied with reception signals received via respective antenna elements, and the results are summed up, thereby to execute control of the reception directivity pattern as the directivity pattern of the overall array antenna system. Alternatively, after appropriate antenna element weight coefficients are multiplied with respective transmission signal, the respective transmission signals are transmitted via the respective antenna elements, thereby to control the transmission directivity pattern as the directivity pattern of the overall array antenna system.
For such an array antenna, there is a sector-antenna-wise method that directs only a main lobe along a desired direction, but does not emit unnecessary radio waves via low side lobes along an undesired direction. In addition, there is a method for improving a SINR (signal-to-interference-and-noise ratio) in the manner that the main lobe is directed along a direction of a desired mobile station, but null is directed to an interferential mobile station.
As another example of a wireless communication apparatus utilizing a multi-antenna system, a MIMO (Multi-Input Multi-Output) communication technique has been drawing attention. The technique is based on a communication apparatus in which pluralities of antenna elements are provided on the respective sides of a transmitter and a receiver, thereby to realize pluralities of spatially multiplexed MIMO channels. On the side of the transmitter, transmission data transmitted by being distributed into a plurality of streams by using a plurality of antennas, and on the side of the receiver, signal processing is executed on the space signals received via the plurality of antennas, and the signal in each of the streams is extracted without crosstalk (refer to Patent Publication 1, for example). For example, in IEEE802.11n, the OFDM_MIMO system using OFDM for the primary modulation is employed. According to the MIMO communication scheme or system, an increase in transmission capacity can be implemented corresponding to the number of antennas, and improvement of the communication speed can be accomplished without introducing an increase in frequency band.
As a representative example of the MIMO communication apparatus, an SVD-MIMO system using singular value decomposition (SVD) of a channel function H (refer to Non-patent Publication 1, for example). In SVD-MIMO transmission, UDVH is acquired by executing singular value decomposition of a numeric value matrix formed from elements of channel information corresponding to a respective antenna pair, that is, a channel information matrix H, whereby V is provided as an antenna weight coefficient matrix on the transmitting side, and (UD)H is provided as an antenna weight coefficient matrix on the receiving side (where U and V are unitary matrixes, and D is a diagonal matrix). Thereby, the respective MIMO channel is represented as the diagonal matrix D having square roots of respective singular values λi. More specifically, a plurality of communication lines logically independent and spatial-orthogonally multiplexed are realized. Thereby, on the side of the receiver, a plurality of original signal sequences can be extracted completely without crosstalk, so that a logically best performance can be accomplished.
In any of the multi-antenna techniques, when a match is not attained between the transmission and reception directivity patterns of the communication apparatus, the main lobe is directed along the same desired direction both in transmission and reception, even higher throughput is expected. An event in which the transmission and reception directivity patterns match with one another is expressed also with an expression "reversible." For example, in MIMO communication, when a channel matrix in the direction from the transmitter to the receiver is "H_down," and a channel matrix in the direction from the transmitter to the receiver is "H_up," the reversibility is represented by the equation "H_up=H_downT" (where T represents the transpose of the matrix).
However, in a practical adaptive array antenna, the reversibility is lost because of, for example, variations in characteristics of the respective elements constituting the transmission and reception systems and in line lengths. As such, even when weight coefficient calculated in the event of reception is used as it is in the event of transmission, a match between the reception directivity pattern and the transmission directivity pattern is not attained.
In the adaptive array antenna, in order to compensate for irreversibility, a correction value calculation process called "calibration" is preliminarily executed, and the correction value acquired by the process is used to correct for the weight coefficient, thereby to attain the match between the reception directivity pattern and the transmission directivity pattern.
Also in the MIMO communication apparatus, spatial transfer functions and transfer functions of analog portions in the device are summed up and recognized in the form of the channel function H in a digital processing portion. Consequently, the reversibility is not established because of differences in the transfer functions of the transmission and reception analog portions. Then, the reversibility has to be established by executing pre-communication calibration of the analog portions.
Antenna calibration methods are broadly classified into, for example, a device-external calibration and a device-internal calibration (or, a self-calibration).
The device-external calibration uses a calibration transmitter/receiver in addition to the adaptive array antenna communication apparatus. When having received a reference signal transmitted from the respective antenna elements of the adaptive array antenna, the transmitter/receiver retransmit the signal. In the adaptive array antenna communication apparatus, the received reference signal looped back from the transmitter/receiver and an original reference signal are compared with one another. Then, variations in the characteristics of respective transmission and reception systems including the antennas and propagation paths are detected and corrected.
In the self-calibration in which the communication apparatus itself compensates for the transfer function, the reference signals generated in the respective transmission systems are looped back to the reception system. Then, the respective received reference signals are compared with original reference signals, and variations in the characteristics of the respective transmission and reception systems including the antennas and propagation paths are detected and corrected.
According to the device-external calibration, since, for example, calibration antennas are necessary in addition to the array antenna, and reference signals looped back via the propagation paths are received, a problem arises in that the calibration is likely to be influenced by, for example, the ambient environment and the signal to noise ratio. The present inventors contemplates that the self-calibration enabling the calibration to be completed within the communication apparatus is preferable.
As an example, an adaptive array antenna such as described hereinbelow has been proposed (see Patent Publication 2, for example). According to the antenna, a portion between each of a plurality of antenna elements is short-circuited, and a reference signal is supplied to one of a plurality of transmitter devices, thereby transmitting the reference signal to an other antenna element from an antenna element corresponding to the transmitter device. Then, a comparison is made between the reference signal received via an antenna element and a reference signal directly transmitted from a reference signal supply device, whereby the characteristics of receiver devices and transmitter devices are evaluated, and weight coefficients are corrected in accordance with the evaluation results. In this case, while the antenna elements are included, appropriate calibration can be implemented without being affected by radio wave propagation environments.
By way of example, the following will describe a system including three transmission and reception branches. A branch number is represented by i, and a transfer function of a transmission analog portion belonging to the i-th branch is represented by Tx(i), the transfer function of a reception analog portion is represented by Rx(i), and a calibration factor to be used as a correction value for the antenna of the respective branch is represented by K(i). In this case, in order to compensate for the transfer function of the respective transmission analog portion, calibration can be executed in such a manner that the correction coefficient K(i) is multiplied with a transmission signal in a digital processing portion. Then, as shown in an expression below, when the ratio between the transmission analog portion and reception analog portion of the respective branch is constant, the calibration is completed.
                    [                  Expression                                                              1                ]                                                                                T                x                                                          (                0                )                                      ×                          K                                            (                0                )                                                                        E              x                                                  (              0              )                                      =                                                                              T                  x                                                                  (                  1                  )                                            ×                              K                                                  (                  1                  )                                                                                R                x                                                          (                1                )                                              =                                                                      T                  x                                                                  (                  2                  )                                            ×                              K                                                  (                  2                  )                                                                                R                x                                                          (                2                )                                                                        (        1        )
According to the self-calibration, a calibration factor is acquired by looping back a signal in a communication apparatus of the type including a multi-antenna system. A method for obtaining a calibration factor by using loopback transfer functions acquired from a looped back signal will be described herebelow.
A loopback transfer function to be acquired from the transmission branch i via a reception branch j is represented as D(i,j). For example, in the event of calibration with a 0-th transmission and reception branch being set to a reference branch, loopback transfer functions of paths for transmission from the branch 0 to other branches 1 and 2 and loopback transfer functions of paths looped back from the respective other branches 1 and 2 and for reception at the branch 0 are acquired, as shown in an expression below.[Expression 2]D(0,1)=Tx(0)×Rx(1)D(0,2)=Tx(0)×Rx(2)D(1,0)=Tx(1)×Rx(0)D(2,0)=Tx(2)×Rx(0)  (2)
When a calibration factor K(0) at the branch 0, which is the reference branch, is set to 1.0 that corresponds to reference value, the calibration factors of the respective branches 0 to 2 are represented as shown below.
                    [                  Expression                                                              3                ]                                                                                K                                      (              0              )                                =          1.0                                                                                K                                      (              1              )                                =                                                    D                                                  (                                      0                    ,                    1                                    )                                                            D                                                  (                                      1                    ,                    0                                    )                                                      =                                          {                                                                            R                      x                                                                                (                      1                      )                                                                                T                      x                                                                                (                      1                      )                                                                      }                            ×                              {                                                                            R                      x                                                                                (                      0                      )                                                                                T                      x                                                                                (                      0                      )                                                                      }                                                                                K                                      (              2              )                                =                                                    D                                                  (                                      0                    ,                    2                                    )                                                            D                                                  (                                      2                    ,                    0                                    )                                                      =                                          {                                                                            R                      x                                                                                (                      2                      )                                                                                R                      x                                                                                (                      2                      )                                                                      }                                                          {                                                                            R                      x                                                                                (                      0                      )                                                                                T                      x                                                                                (                      0                      )                                                                      }                                                                        (        3        )
When the respective results in Expression (1) are verified, it can be known that, as shown in an expression below, the condition that the ratios between the transfer functions of the transmission analog portions and reception analog portions of the respective branches are constant is satisfied.
                    [                  Expression                                                              4                ]                                                                                T                  x                                                                  (                  0                  )                                            ×                              K                                                  (                  0                  )                                                                                R                x                                                          (                0                )                                              =                                                    T                x                                                          (                0                )                                                                    R                x                                                          (                0                )                                                                                T                  x                                                                  (                  1                  )                                            ×                              K                                                  (                  1                  )                                                                                R                x                                                          (                1                )                                              =                                                    T                x                                                          (                0                )                                                                    R                x                                                          (                0                )                                                                                T                  x                                                                  (                  2                  )                                            ×                              K                                                  (                  2                  )                                                                                R                x                                                          (                2                )                                              =                                                    T                x                                                          (                0                )                                                                    R                x                                                          (                0                )                                                                        (        4        )
Since the calibration is executed in accordance with the 0-th branch set to the reference, the calibration factor K(0) of the 0-th branch is 1.0, as shown in Expression (3). Further, the calibration factors K(i) of the other branches respectively take values commonly multiplied with the value "{Tx(0)/Rx(0)}" of the 0-th branch.
In the course of the self-calibration, the loopback for transmitting the reference signal from the reference branch to the other branch, herebelow, will be referred to as "forward loopback." In addition, the loopback for receiving the reference signal looped back from the other branch at the reference branch, hereinbelow, will be referred to as "backward loopback."
It is known to the skilled in the art that there occurs a difference in a synchronizing circuit in an actual communication apparatus simply configured. Because of such a difference in the synchronizing circuit, the transfer function is varied in the event of looping back of a reference signal. In particular, in a case using the OFDM modulation scheme, the circuit has a characteristic in that the amount of phase rotation associated with a synchronization timing delay is different in units of a subcarrier.
When the forward loopback and the backward loopback are finely different from one another, the loopback transfer functions are different in appearance from one another. Variations in the transfer functions due to a difference in the synchronization positions in the forward loopback event and the backward loopback event, respectively, are represented by F and B, the apparent forward loopback transfer function is represented as D(0,1)F, D(0,2)F, and the apparent backward loopback transfer function is represented as D(1,0)B, D(2,0)B.
In the case as described above, when, as shown in Expression (3) with the 0-th branch set to the reference branch, the calibration factors of the respective branches are acquired, the results are represented as shown below.
                    [                  Expression                                                              5                ]                                                                                K                                      (              0              )                                =          1.0                                                                                K                                      (              1              )                                =                                                                      D                                                        (                                          0                      ,                      1                                        )                                                                  F                                                              D                                                        (                                          1                      ,                      0                                        )                                                                  B                                      =                                          {                                                                            R                      x                                                                                (                      1                      )                                                                                T                      x                                                                                (                      1                      )                                                                      }                            ×                              {                                                                            R                      x                                                                                (                      0                      )                                                                                T                      x                                                                                (                      0                      )                                                                      }                            ×                              {                                  F                  B                                }                                                                                K                                      (              2              )                                =                                                                      D                                                        (                                          0                      ,                      2                                        )                                                                  F                                                              D                                                        (                                          2                      ,                      0                                        )                                                                  B                                      =                                          {                                                                            R                      x                                                                                (                      2                      )                                                                                T                      x                                                                                (                      2                      )                                                                      }                            ×                              {                                                                            R                      x                                                                                (                      0                      )                                                                                T                      x                                                                                (                      0                      )                                                                      }                            ×                              {                                  F                  B                                }                                                                        (        5        )
According to the expression, at the respective branch 1, 2, which is other than the reference branch, {F/B} indicative of the variation in the transfer function due to the difference in the synchronization positions is reflected in the respective calibration factor K(1), K(2). In addition, the ratio between the transfer function of the transmission analog portion and the transfer function of the reception analog portion is constant. Thereby, the calibration condition is satisfied. In comparison, however, in the case of the branch 0 as the reference branch, {F/B} indicative of the variation in the transfer function due to the difference in the synchronization position is not reflected in the calibration factor K(0) thereof. In other words, only the calibration factor of the reference branch has an error.
[Patent Publication 1]    Japanese Unexamined Patent Application Publication No. 2002-44051
[Patent Publication 2]    Japanese Unexamined Patent Application Publication No. 2003-124731
[Non-Patent Publication 1]    http://radio3.ee.uec.ac.jp/MIMO(IEICE_TS).pdf (as of Oct. 24, 2003)

Wireless communication apparatus, antenna calibration method, and computer program


Sliding parts are provided wherein a plurality of pumping areas for generating pumping action via the relative rotational sliding of a stationary ring and a rotating ring is discontinuously formed in a circumferential direction on a sealing face of one of the stationary ring and rotating ring so as to communicate with a sealed fluid-containing space. The pumping areas are provided with intake pumping areas operating in a direction in which the sealed fluid is drawn in and outflow pumping areas operating in a direction in which the sealed fluid is expelled. A plurality of dynamic pressure-generating grooves for generating dynamic pressure via the relative rotational sliding of the stationary ring and the rotating ring are formed in a circumferential direction on a sealing face of the other of the stationary ring and the rotating ring so as to communicate with the sealed fluid-containing space.

In sealing apparatuses for preventing the leakage of a sealed fluid, such apparatuses comprising two parts configured so as to rotate relatively to one another and so that end surfaces thereof slide along a plane, such as, for example, a mechanical seal, a balance must be struck between the two opposing conditions of seal tightness and lubrication in order to maintain seal integrity for extended periods of time. In recent years, environmental concerns in particular have led to an increase in demand for reduced friction in order to reduce mechanical damage while preventing sealed fluid leakage. Methods of reducing friction include the so-called fluid lubrication state, in which dynamic pressure is generated between sealing faces due to rotation, and the surfaces slide with a liquid film interposed therebetween. However, in such cases, positive pressure is generated between the sealing faces, so that the fluid escapes from the positive pressure portion outside of the sealing faces. Such fluid outflow constitutes leakage in the case of a seal.
Mechanical seals such as that shown in FIG. 10, in which dynamic pressure is generated between sealing faces via rotation, are known in the art ("first prior art"; see, for example, patent document 1). In the first prior art shown in FIG. 10, a plurality of radial direction grooves 32R, 32L for generating dynamic pressure during rotation is provided in the circumferential direction of a sealing face 31 of a mating ring 30 constituting one of a pair of sliding parts, with tapering surfaces 33R, 33L tapering in opposite directions being formed following the circumferential direction so that the boundary between one pair of radial direction grooves 32R, 32L is in a trough formed by the tapering surfaces, and a dam part 34 being formed at the boundary so as to separate the radial direction grooves 32R, 32L.
As shown in FIG. 10(b), when the sliding parts rotate relative to each another, the pressure in the radial direction groove 32R, which lies in the upstream direction of a gas flow G, decreases, creating negative buoyancy, and the wedge effect of the tapering surface 33L in the radial direction groove 32L on the downstream side of the dam part 34 increases pressure, creating positive buoyancy. At this time, the action of the dam part 34 decreases the negative pressure and increases the positive pressure, creating a net positive pressure and allowing a strong buoyancy to be obtained.
Meanwhile, the inventors have already filed a patent application for sliding members for a mechanical seal for sealing a sealed fluid present on one side in the radial direction of relatively rotationally sealing faces, wherein a plurality of grating portions 50, in which a plurality of parallel rectilinear indentations are formed at a predetermined pitch within a predetermined area, is discontinuously formed in a circumferential direction in an area between radii R2 and R3 on a sealing face 51 having an internal diameter R1 and an external diameter R4; the rectilinear indentations of the plurality of grating portions being formed so that the direction thereof inclines at a predetermined angle relative to the sliding direction of the sealing face, thereby improving the introduction and retention of the sealed fluid between the sealing faces, and allowing stable and favorable lubrication to be obtained, as shown in FIG. 11 ("second prior art;" cf. patent document 2).
In methods utilizing dynamic pressure to mitigate sliding resistance, as in the case of the first prior art, dynamic pressure is not generated until the shaft reaches a certain degree of rotational speed. For this reason, sufficient quantities of sealed fluid cannot be introduced between the sealing faces during the period from when rotation begins until dynamic pressure is generated, leading to a reduction in lubrication. When there is not a sufficient amount of sealed fluid between the sealing faces, torque increases, leading to the problems of seizing, vibration, noise, and the like being generated and sliding resistance becoming unstable.
The second prior art also has the problem that, because the height of the rectilinear indentations within the plurality of grating portions is on the order of 1 μm or less, a sliding member is deformed by heat, pressure, or load when operated for extended lengths of time in environments of high heat or pressure, partially increasing the size of the gap formed with the counterpart sliding member, so that the introduction and retention of the sealed fluid between the sealing faces cannot be controlled by fine indentations of roughly 1 μm in height.


A method for converting two-dimensional images into three-dimensional images includes: tracking an object in an image, the object having an object edge and an object outline thereabout, from frame to frame over a sequence of images; and creating object outlines in subsequent frames for converting two-dimensional images into three-dimensional images maintaining an object outline to object edge distance spacing relationship as the object moves or changes from frame to frame.

In the process of converting a two-dimensional (2D) image into a three-dimensional (3D) image, at least two perspective angle images are needed independent of whatever conversion or rendering process is used. In one example of a process for converting two-dimensional images into three-dimensional images, the original image is established as the left view, or left perspective angle image, providing one view of a three-dimensional pair of images. In this example, the corresponding right perspective angle image is an image that is processed from the original image to effectively recreate what the right perspective view would look like with the original image serving as the left perspective frame.
In the process of creating a 3D perspective image out of a 2D image, as in the above example, objects or portions of objects within the image are repositioned along the horizontal, or X axis. By way of example, an object within an image can be "defined" by drawing around or outlining an area of pixels within the image. Once such an object has been defined, appropriate depth can be "assigned" to that object in the resulting 3D image by horizontally shifting the object in the alternate perspective view. To this end, depth placement algorithms or the like can be assigned to objects for the purpose of placing the objects at their appropriate depth locations.
In a motion picture, objects typically move (i.e., change position within the image, from frame to frame). An unfortunate consequence of some processes for converting two-dimensional images into three-dimensional images is that noticeable visual artifacts appear (e.g., as flickering or shuttering pixels) at object edges as objects move from frame to frame.
In view of the foregoing, it would be desirable to be able to convert two-dimensional motion pictures into three-dimensional motion pictures in such a manner that motion artifacts are significantly minimized or eliminated.

Method for minimizing visual artifacts converting two-dimensional motion pictures into three-dimensional motion pictures


A drive controller comprises an evaluation unit to receive and evaluate a first item of feedback information from a motor connected to the drive controller, a control-signal block connected to secure inputs of the drive controller to receive condition control signals and to provide the condition control signals as input signals, a drive-signal block connected to the evaluation unit to calculate a first speed and/or a first position on the basis of the first item of feedback information on at least a first channel and to provide a first speed signal and/or a first position signal, a programmable logic unit connected to the control-signal block and the drive-signal block to realize the safety functions and the speed signal and/or the position signal to provide switch-off signals, and an output unit connected to the logic unit and to secure outputs of the drive controller to output switch-off signals on safety-switch-off paths.

Drive units usually consist of a motor, of a power electronics and of a drive controller. The power electronics supplies the motor with the current necessary to sustain motion. From the signals of a sensor at the motor, the drive controller determines speed and position of the motor and carries out speed and position control by a corresponding activation of the power electronics. A safety brake in the motor which is usually provided furthermore serves to maintain the position of the motor even in a power-off state, e.g. after switching off the machine.
Increasingly, a safety device having safety functions is integrated into the drive controller, e.g. as a plug-in card. Any essential danger of body injury that may occur at the machines results from the dynamic motion of the drive unit. Integrating the safety device having safety functions into the drive controller allows for short response times compared to an external safety controller. The safety device having the safety functions in the drive controller serves to switch the motor in a torque-free manner and to monitor speed and position. Moreover, the safety device usually controls the safety brake in the motor, as well.
Each desired safety function is firmly stored in the safety device of the drive controller and may be activated by parameterizing. Therefore, the functionalities of the safety functions are predetermined. As a result, the safety functions are limited to the developmental state of the safety device at the point in time when it was integrated into the drive controller.
Moreover, the time and effort involved in implementation is high as every safety function in the safety device has to be fully programmed. Testing, too, takes up additional time as the safety functions have to be fully tested with many different parameterizations.
In addition, it is not possible for the user to extend the safety functions; this may only be done on behalf of the manufacturer by changing the software in the safety device. Moreover, executing the safety functions in the drive controller requires a lot of time as the safety functions that are available always have to be run through, even if they are currently not utilized by the user.
A generic safety device of a drive controller is disclosed in DE 102 61 452 A1. DE 10 2009 938 060 A1 further discloses a validity check of two measured values in a drive unit.


An electrical control system for distinguishing between an electrical fault and a shaft shear condition in a gas turbine engine, the control system including, in one aspect, a detection circuit including: two or more probes, each probe including an associated resistor having a predetermined range of resistance, and each probe being disposed in the engine adjacent a rotary mounted shaft component, where mechanical interference between one or more of the probes and the shaft component renders the associated resistor substantially non-conductive; sensor processor(s) in communication with each probe, determining a probe operational status based on a measured resistance to current conducted through each probe, and generating a fault code when the measured resistance of at least one of the plurality of probes is not within the predetermined range of resistance.

Shaft shear in a gas turbine engine is a potentially catastrophic condition where, for example, the low pressure shaft has broken, the shaft portions continue rotating and the aft portion is driven aftward due to gas flow over the low pressure turbine. Rapid engine shutdown is required and specifically the fuel supply to the engine must be terminated immediately to prevent the resulting unloaded turbine from accelerating up to the turbine burst speed.
To detect shaft shear conditions by, for example, subsequent axial motion of the shaft to the aft position, sensors or probes are positioned in the engine adjacent the rear end of the shaft. When the shaft collides with the sensors, electronic controls generate a signal that results in fuel supply termination and engine shutdown.
Since the shaft shear condition and complete loss of engine operation are potentially catastrophic to the engine and aircraft, multiple sensors are installed to provide the necessary redundancy and reliability.
However any electronic sensor can malfunction due to internal damage, or the circuit connected to the sensor may be faulty. The sensors are housed in the engine core surrounded by the hot gas path, subjected to vibration and adjacent rotary components operating at high speed.
Therefore there is a need for reliable sensor operation which can properly detect shaft shear while minimizing false alarms.
Features that distinguish the present disclosure from the background art will be apparent from review of the disclosure, drawings and description of the disclosure presented below.

Electronic shaft shear detection conditioning circuit


A vehicle situation that can occur at a later time than the current time is displayed on a first display device, a second display device, and a third display device, and display content is controlled so that a display content of the second display device includes a vehicle situation that can occur at a later time than the vehicle situation displayed on the first display device, and a display content of the third display device includes a vehicle situation that can occur at a later time than the vehicle situation displayed on the second display device.

Conventionally, a technique has been proposed in which a display area of a display device mounted on a vehicle is divided depending on information content.
For example, Patent Literature 1 discloses an information display system for a vehicle that groups content of information to be recognized by a driver and divides a display area of a head-up display depending on the grouped content. In a windshield on which information displayed in the head-up display is displayed, information having a high degree of importance is displayed in a display area closer to the gaze of a driver gazing a travel path in front of the vehicle, and information having a low degree of importance is displayed in a display area farther from the gaze.


Filtered feedthrough assembly (100, 200) is formed by mounting a filter support assembly (130, 130', 230) having a capacitor (110,210) mounted thereto, to a conductive feedthrough (10, 10'). The conductive feedthrough includes a metallic ferrule (14, 14') having a centrally disposed through opening (28) extending between opposing ends thereof. At least one elongate lead wire (12) extends through the ferrule through opening. A hermetic seal insulator (20, 20') is disposed within the central opening of the ferrule and is sealed thereto. The filter support assembly (130, 130', 230) includes an insulative substrate (132, 132', 132") having a first metallization pattern (133, 314) formed on an upper surface (138, 138") thereof. A second metallization pattern (135, 316) is formed on the lower surface (124, 124') of substrate (132, 132', 132"). A capacitive element (110, 210) is electrically coupled between a first metallization area (145, 318) and second metallization area (143,320) of the first metallization pattern (133, 314). The first metallization area (145, 318) is electrically coupled to the lead (12) and the second metallization area (143, 320) is electrically coupled to the ferrule (14, 14'). The second metallization area (145, 318) includes a metallized recess (140, 140') formed in a perimeter edge (134, 134') of the substrate (132, 132', 132"). A conductive contact material (150) is disposed within the recess for providing the electrical connection to the ferrule (14, 14'). A conductive contact material (152) provides the electrical connection between the lead (12) and the first metallization area (145, 318).

1. Field of the Invention
This invention is directed to a filtered feedthrough assembly having at least one lead wire. In particular, this invention directs itself to a feedthrough assembly utilizing at least one capacitor element coupled between the lead wire and a metallic ferrule of the feedthrough. Still further, this invention directs itself to a filtered feedthrough for use in implantable medical devices wherein the capacitor is affixed to an insulative substrate, with the substrate being secured to the conductive feedthrough device. Still further, this invention directs itself to a filtered feedthrough wherein the substrate has a polygonal contour with at least a portion of the edges thereof having metallized recesses formed therein. The metallized recesses define spaces into which conductive contact material may be applied to provide an electrical connection with the metallic ferrule of the feedthrough device.
2. Prior Art
Filtered feedthrough devices are well known in the art. The best prior art known to the Applicants include U.S. Pat. Nos. 3,329,911; 3,443,251; 3,617,830; 3,879,691; 4,152,540; 4,314,213; 4,424,551; 4,642,589; 4,673,900; 4,675,629; 4,682,129; 4,698,605; 4,700,155; 4,700,440; 4,772,225; 4,791,391; 4,804,332; 4,819,130; 4,853,824; 4,872,085; 4,887,185; 4,984,129; 5,032,949; 5,150,086; 5,153,540; 5,206,786; 5,132,522; 5,287,076; 5,333,095; 5,406,444; and the following Publications: "Cellular Phones May Affect Use of Pacemakers", The Wall Street Journal, Friday, Apr. 28, 1995, pp. B1-B3; "EMI Filtering in Medical Implantables", Medical Devices in Diagnostic Industry, September 1994; "Do European GSM Mobile Cellular Phones Pose a Potential Risk to Pacemaker Patients?", Pace, Vol. 18, June 1995, pp. 1218-1224; and, "Ceramic EMI Filters--A Review", Ceramic Bulletin, Vol. 67, No. 4, 1988, pp. 737-746.
Filtered feedthrough devices have been employed in implantable devices, as disclosed in U.S. Pat. No. 4,152,540 and the publication entitled "EMI Filtering in Medical Implantables". Such filtered feedthrough devices are known to employ discoidal capacitors in single lead feedthrough devices and discoidal capacitor arrays in multi-lead assemblies. Many of such feedthrough devices incorporating such capacitive elements had to be specially manufactured to provide a cavity into which the capacitor or capacitor array was to be located, either by creating a recess within the ceramic hermetic sealing element, or extending the metallic ferrule beyond the hermetic seal in order to form such a cavity.
Whereas in the instant invention, individual capacitive elements are positioned on a separate substrate which is subsequently married to the feedthrough. By this arrangement, filtering can be added to a conventional feedthrough device without the requirement for manufacturing special parts, thereby improving the efficiency of the manufacturing operation. Further, the substrate mounted capacitor assembly can be tested prior to its marriage with the conductive feedthrough.
In still other prior art devices, such as disclosed in U.S. Pat. No. 3,617,830, filtered feedthrough devices utilizing chip capacitors are disclosed. Such prior art devices disclosed chip-type filter capacitors positioned between a pair of conductive rings, with the space between the capacitors and the rings being encapsulated with an epoxy filler material. In addition to such materials not providing a high reliability hermetic seal, nor providing a biocompatible structure, such structures do not provide for accommodating capacitors of different sizes, as the chip capacitor is located within a cavity defined by the space between the conductive rings. Therefore, a different diameter outer ring is required for an application requiring larger capacitors, and in any one application all of the capacitors must be the same length irrespective of their capacitive value. With the chip capacitors being disposed within a cavity, the difficulty in replacing any one capacitor, which proves to be defective, is almost as difficult as in the case where discoidal capacitors are utilized.
In systems such as that disclosed in U.S. Pat. No. 4,152,540, and other prior art systems such as that disclosed in U.S. Pat. Nos. 4,424,551 and 5,333,095, filtered feedthrough devices employing discoidal type capacitors are electrically coupled to the respective lead wires and ferrules utilizing conductive adhesive compositions. The system disclosed by U.S. Pat. No. 5,333,095 provides no means for applying a moisture resistant coating to the discoidal capacitive element which has a diameter substantially larger than that of the feedthrough device, making such impractical for use in most modern implantable systems wherein space is at a premium and where the feedthrough devices are manufactured by other than the implantable device manufacturer.
It has long been known that medical implantable devices must operate in an environment which is subjected to electromagnetic interference (EMI). The electrical leads which extend from such implantable devices act as antennas which receive and conduct electromagnetic energy into the electronics of the implanted device. Since the circuits of such medical implantable devices are very sensitive, and reliability is so important, as a fault may be life threatening, medical implantable devices have incorporated filter circuits therein to suppress EMI. In some cases, feedthrough devices employing discoidal type capacitors have been employed in an attempt to filter out the electromagnetic interfering signals before they reach the electronic circuitry of the implantable device. The ability to filter the interference before it reaches the electronics has become more important recently, with the discovery that the electromagnetic interference generated by the new digital cellular phones and other electronic devices is not sufficiently suppressed by prior art electromagnetic interference filters of some current medical implantable devices. The high frequency emissions from the digital cellular phones may be re-radiating within the medical implantable device, bypassing and thereby rendering the "on-board" filters ineffective. It is therefore critical that the filtering take place as close to the source of the emissions as possible, such as at the entrance to the housing of the implantable device. As a result of this ever increasing problem, the use of filtered feedthroughs is increasing and may soon be required by governmental agencies to effectively suppress EMI, and therefore it will be important to efficiently manufacture such, in order to help contain the costs of the implantable medical devices.
Further, for medical devices such as implantable defibrillators, the high voltage output through the feedthrough devices adds another complexity to incorporating a filter capacitor therewith. A capacitor employed in such a device must be physically larger in order to withstand the higher voltage which must be impressed thereon, but the space limitations of the feedthrough used in such defibrillators are not conducive to accommodating large size capacitors. However, utilizing the filtered feedthrough of the present invention, such larger capacitors can be installed without requiring an increase in the physical size of the feedthrough structure. Still further, to suppress high frequency EMI, each lead of a multi-lead feedthrough assembly may be required to be individually tuned, thus, each lead may require a capacitor having a different capacitance, voltage rating or the like, which can be installed in the present invention.

Substrate mounted filter for feedthrough devices


This application provides an application download monitoring method and a device. A mobile terminal detects whether access URL information requested by a plurality of first applications includes an application download request; when detecting that access URL information requested by any one of the plurality of first applications includes an application download request, the mobile terminal blocks the application download request, and sends the URL information to a server; the server queries, based on the application download request in the URL information, whether a security analysis result of a second application corresponding to the application download request exists, and if finding the security analysis result, the server sends the security analysis result to the mobile terminal; and the mobile terminal determines, based on the security analysis result, whether to download the second application.

The mobile Internet is an open system. When browsing a web page or news on a mobile phone, a user may be misled to download some malicious software, thereby compromising user security. In the prior art, download detection and control are usually performed within an application. For example, a browser App (application, Application) detects a link clicked by a user, pops up a prompt box for user confirmation if finding that the link is a download link, and guides the user to a more secure download link.
However, download detection within a single application lacks generality. This solution cannot resolve the problem when many software development kits (software development kit, SDK) for advertising are embedded in various APKs (Android® operating system application package, Android application package), and an advertising component in these APKs is popped up to induce a user to download an application for installation, and consequently the user may still be induced to install some malicious software and the user may still be induced to install some malicious software.

Application download monitoring method and device


A brazing filler metal capable of improving both of oxidation resistance and corrosion resistance is obtained. This brazing filler metal (1, 1d, 51 and 51a) consists of at least a three-layer structure of an Ni—Cr brazing layer (2 and 2a) consisting of an Ni—Cr alloy layer, a Ti brazing layer (3, 3a, 3b, 3c and 3d) consisting of a Ti layer or a Ti alloy layer and an Ni brazing layer (4, 4a, 4b, 4c and 4d) consisting of an Ni layer or an N alloy layer arranged between the Ni—Cr brazing layer and the Ti brazing layer.

The interest in environmental problems has been internationally elevated in recent years, and a cogeneration system employing a fuel cell or a micro gas turbine has been developed and widespread as a link thereof. High-temperature gas flows in a heat exchanger constituting this cogeneration system, and the temperature of this gas tends to increase in order to improve heat generation efficiency. In general, a material prepared by employing stainless steel for a substrate while employing nickel solder (JIS BNi-1 to 7) for a brazing filler metal is known as a heat exchanger material capable of withstanding a severe service condition under such a high temperature. Nickel solder, which is a material excellent in oxidation resistance and corrosion resistance but hard to plasticize, is generally manufactured in a powder state by a liquid quenching method. Thus, nickel solder has been inconveniently high-priced. Further, a debindering step is necessary after brazing since a pasty material prepared by mixing a binder into powdery nickel solder is applied to stainless steel forming the substrate in a manufacturing step for the heat exchanger, and there has been such inconvenience that the manufacturing step is complicated.
In the meantime, there is generally proposed a technique of manufacturing a brazing filler metal consisting of a laminated structure of an Ni-based metal layer and an Ni-based metal layer consisting of an Mn—Ni—Cu alloy by employing rolling/bonding without employing the aforementioned liquid quenching method and brazing/bonding stainless steel with this brazing filler metal. Such a technique is disclosed in International Patent Laying-Open No. WO00/18537, for example. According to this International Patent Laying-Open No. WO00/18537, the Mn—Ni—Cu alloy is made to contain Cr, Ti etc. to be not more than 5 mass % in total, thereby improving oxidation resistance.
In general, further, there is known a technique of employing a Ti—Ni-based brazing filler metal consisting of two layers, i.e., a Ti or Ti-based alloy layer and an Ni or Ni-based alloy layer having high corrosion resistance as a brazing composite material prepared by rolling/bonding without employing the aforementioned liquid quenching method. Such a technique is disclosed in Japanese Patent Laying-Open No. 2003-117678, for example. In this Japanese Patent Laying-Open No. 2003-117678, an Ni—Cr—Fe-based anticorrosion/heat-resistant superalloy is listed as an Ni alloy.
However, the Mn—Ni—Cu alloy constituting part of the conventional brazing filler metal disclosed in the aforementioned International Patent Laying-Open No. WO00/18537 has such a problem that it is difficult to improve corrosion resistance of a portion bonded by brazing/bonding since Mn and Cu having low corrosion resistance are contained in the alloy.
Further, the conventional Ti—Ni-based brazing filler metal disclosed in the aforementioned Japanese Patent Laying-Open No. 2003-117678 has such a problem that it is difficult to obtain high oxidation resistance since no oxide film (passive film) of Cr2O3 is formed on the surface of a portion bonded by brazing/bonding, although the same has high corrosion resistance. Also when the Ni—Cr—Fe-based anticorrosion/heat-resistant superalloy listed in Japanese Patent Laying-Open No. 2003-117678 as the Ni alloy is employed, the rate of reaction between the brazing filler metal and the Ni—Cr—Fe-based anticorrosion/heat-resistant superalloy in brazing is retarded since the melting temperature of the Ni—Cr—Fe-based anticorrosion/heat-resistant superalloy is high (about 1800° C. to about 2000° C.). Thus, the rate of diffusion of Cr from the Ni—Cr—Fe-based anticorrosion/heat-resistant superalloy into the brazed/bonded portion is retarded, and hence there is such inconvenience that Cr is not sufficiently supplied to the brazed/bonded portion. Thus, there is such a problem that it is difficult to obtain high oxidation resistance since no oxide film (passive film) of Cr2O3 of a sufficient quantity is formed on the surface of the portion bonded by brazing/bonding.

Brazing filler metal, brazing composite material and brazed structure brazed/bonded with the same


An assembly for transferring a fluid between a vessel having a body with an open end and a slidable piston positioned within the body and a vial having a penetrable seal. The assembly includes a housing having first and second open ends, and a bore extending between the first and second open ends. The housing is removably connectable to the piston. The assembly also includes a conduit having first and second ends and first and second apertures adjacent to the first and second ends, respectively. The present invention provides for an assembly for transferring a fluid between a vessel having a body with an open end and a slidable piston positioned within the body and a vial having a penetrable seal. The assembly includes a housing having first and second open ends, and a bore extending between the first and second open ends. The housing is removably connectable to the piston. The assembly also includes a conduit having first and second ends and first and second apertures adjacent to the first and second ends, respectively.

Traditionally, a syringe is filled manually by aspirating a liquid pharmaceutical component from a pharmaceutical vial having a neck with a penetrable closure into the syringe through a needle that penetrates the penetrable closure. The method of manually filling the syringe typically includes the following steps: (a) drawing air into the body of the syringe by pulling the syringe's plunger away from the needle end of the syringe until the volume of air in the body approximately equals the volume of pharmaceutical component to be loaded into the syringe; (b) carefully aligning the needle with the vial's penetrable closure and inserting the needle through the penetrable closure into the vial; (c) inverting the vial and forcing the air from the body of the syringe into the vial by advancing the syringe's plunger; (d) withdrawing the plunger to draw out the desired volume of the pharmaceutical component into the syringe; and (e) removing the needle from the vial.
This method suffers from various disadvantages. Firstly, the user is exposed to the unprotected needle tip, which can result in accidental stabbings or prickings to the user. Secondly, if the user wishes to draw a large volume of the pharmaceutical component into the syringe (e.g., 10 cc) an equivalent volume of air must be forced into the vial. This can increase the pressure in the pharmaceutical vial to the point where the pharmaceutical component may spray through the puncture point made by the needle in the penetrable seal and onto the user. These accidents are particularly dangerous if the pharmaceutical component is unsafe to the user, for example toxic oncology pharmaceuticals. Thirdly, the sterility of the needle may be compromised during the process of transferring the pharmaceutical component from the vial to the syringe.
Additionally, many pharmaceutical preparations must be distributed and stored as two or more separate components (commonly a solid lyophilized component and a liquid component). The two components are mixed just prior to administration. In the case of a solid and liquid component, the solid component is reconstituted by: (a) providing a first solid component packaged in a pharmaceutical vial having a neck closed by a penetrable closure; (b) providing a second liquid component in a syringe; (c) injecting the second liquid component into the vial through the penetrable closure; (d) swirling the vial impaled on the syringe to dissolve, dilute or suspend the first solid component in the second component; and (e) aspirating the combined components back into the syringe. Alternatively, the two or more components may be liquid and require mixing just prior to administration. The mixing may be accomplished in an analogous manner. These methods suffer from many of the disadvantages described above.

Pharmaceutical delivery systems and methods for using same


A fundamental period calculation circuit calculates a fundamental period in accordance with a plurality of pulses including reproduction target pulses included in binary reproduced output signal pulses sequentially input as digital signal pulses to be reproduced. A clock generator generates a demodulation clock having the fundamental period calculated by the fundamental period calculation circuit. A phase error amount detecting circuit detects a phase error amount in accordance with a phase difference between the demodulation clock generated by the clock generator and a plurality of pulses including the reproduction target pulses. A synchronizing circuit controls the phase error amount of a generation timing of the demodulation clock by the clock generator to a predetermined value in accordance with the phase error amount detected by the phase error amount detecting circuit so that the demodulation clock generated by the clock generator is synchronized with each of the reproduction target pulses. A demodulator sequentially demodulates the binary reproduced output signal pulses in accordance with the demodulation clock from the clock generator, the demodulation clock being synchronized with each of the reproduction target pulses with the predetermined phase error amount by the synchronizing circuit.

1. Field of the Invention
The present invention relates to a digital signal reproducing apparatus and, more particularly, to a digital signal reproducing apparatus for reproducing a digital signal recorded by an arbitrary self-clock scheme (e.g., an MFM modulation scheme or a 2-7 modulation scheme) on a recording medium such as a floppy disk, a magnetic card, an optical card, or an optomagnetic medium.
2. Description of the Related Art
Various conventional digital signal recording/reproducing schemes used in a variety of fields described above have been proposed. An arbitrary self-clock scheme has been generally used because it can extract a clock signal from a signal modulated during recording. In reproduction of a digital signal recorded by such an arbitrary self-clock scheme on a recording medium, a countermeasure against variations in reproduction pulse width caused by variations in relative speed between the recording medium and a read head and signal variations and omissions caused by damage and dust on the medium must be implemented to accurately demodulate the recorded digital signal regardless of the types of self-clock schemes.
Conventional digital signal reproducing apparatuses include an analog reproducing apparatus for feeding back a phase difference between a reproduced pulse and a self-oscillated clock pulse to a frequency to synchronize the reproduced pulse with a read pulse according to a PLL (Phase-Locked Loop), and a digital reproducing apparatus for reading pulses one by one using a reproduced pulse as a reference pulse to form a window signal.
The former analog prior art is disclosed in Published Examined Japanese Patent Application No. 57-24700 although the disclosed arrangement partially includes a digital arrangement. In the arrangement of this prior art, a read clock synchronized with a reproduced pulse is obtained by a PLL scheme for counting a phase difference between a reproduced pulse and a self-oscillated clock and feeding back a count value to the frequency of the self-oscillated clock. The reproduced pulse is demodulated by the read clock synchronized with the reproduced pulse.
The latter digital prior art is exemplified by Published Unexamined Japanese Patent Application No. 62-241176. In an arrangement proposed by this prior art, the period of a clock bit at a given moment is extracted from a pulse interval during reproduction at the given moment, a correction clock having a value 1/2 the period of the extracted clock bit as a reference period is generated, and a read window signal is formed on the basis of the correction clock, thereby demodulating a reproduced pulse.
In Published Examined Japanese Patent Application No. 57-24700 disclosing the arrangement wherein the phase difference between the reproduced pulse and the self-oscillated clock is fed back to the frequency of the self-oscillated clock to obtain the read clock synchronized with the reproduced pulse, once the phase of the reproduced pulse is stepped out from that of the read clock, it takes a long period of time to properly phase-lock the read clock with the reproduced pulse. In addition, tracking is delayed when variations in medium speed causing large pulse width variations occur. As a result, the reproduced pulse cannot be accurately demodulated, resulting in inconvenience.
In Published Unexamined Japanese Patent Application No. 62-241176 disclosing the arrangement wherein the period of the clock bit is extracted from the pulse interval corresponding to the reception timing of the pulse to form the demodulation window, the clock period varies upon reception of each pulse. For this reason, when the pulse position is abruptly changed due to variations in speed of the medium, a demodulation error occurs. For example, if the current pulse position is delayed from the normal position, the duration of a pulse preceding the current pulse is increased, and the duration of a pulse succeeding the current pulse is decreased. For this reason, when the clock period is increased in accordance with the preceding pulse, the next pulse does not reach within the window ON period, and accurate demodulation cannot be performed. For example, when the pulse width is abruptly increased by jitter (fluctuation of a one-shot signal) caused by damage and dust on the medium and the next pulse width is decreased, a bit cannot be fitted within the data window. As a result, the clock bit and the data bit are reversed in order to cause a demodulation error.
The latter digital prior art is susceptible to variations by jitter. More specifically, in an apparatus for reproducing a digital signal recorded on a recording medium, jitter caused by variations in read speed of the recording medium easily affects reproduction. At the same time, jitter such as variations in reproduced pulse width caused by damage and dust on the recording medium also adversely affects reproduction. It is, therefore, difficult to accurately demodulate a digital signal (data) modulated and recorded by an arbitrary self-clock scheme.

Digital signal reproducing apparatus for reducing influence by jitter


A flatbed railcar is provided which may be utilized for the transport of relatively lightweight bulky articles, as well as relatively heavy articles such as steel beams. The railcar includes a number of components which cooperate to allow such diversity of uses. A rectangular base structure is provided. A substantially planar deck is secured to the upper surface of the rectangular base structure. A plurality of rail wheel assemblies are coupled to the lower surface of the base structure. The rail wheel assemblies are adapted for engaging a railroad. A first bulkhead member is coupled to a first end of the base structure. A second bulkhead member is coupled to the second end of the base structure. A vertical center partition member is also provided. The vertical center partition member is substantially perpendicular to the base structure. It is located along a longitudinal centerline relative to the base structure. It extends between the first and second bulkhead members, and is coupled to the first and second bulkhead members in force-transference relationship therewith. The vertical center partition member provides lateral bending stiffness, vertical bending stiffness, and torsional stiffness. The vertical center partition is substantially uniform in width over its duration. This facilitates loading and unloading operations utilizing overhead cranes. A plurality of relatively wide, adjustable support straps are coupled to the base structure to safely tie down the cargo with out damaging the cargo.

1. Field of the Invention
The present invention relates in general to rail cars, and in particular to rail cars which are utilized for carrying bulky items ranging from lumber and drywall to steel bars.
2. Description of the Prior Art
In the prior art, a certain type of railcar, which is known as a xe2x80x9ccenterbeam railcar,xe2x80x9d is utilized to carrying lumber and drywall. Because the loads are relatively light, the centerbeam railcar need not be excessively reinforced. Additionally, centerbeam railcars are not generally useful for carrying steel beams or other similar heavy loads, since the loading requirement for a steel-carrying railcar is substantially greater than that of lumber-carrying railcars.
In a centerbeam car, a central partition is provided which runs along the longitudinal axis of the railcar between relatively lightweight bulkheads. A structural section is provided which is generally horizontal to the bed of the car. This horizontal structural section is referred to as the xe2x80x9ctop section.xe2x80x9d In the prior art, the top section is about three feet wide, runs the full length of the car, and serves to give the car much of its lateral stiffness, vertical bending stiffness, and torsional stiffness. However, the horizontal structural section impedes the utilization of overhead cranes for loading; instead, forklifts and other lateral lifting devices are utilized.
A series of risers are provided on the deck of the prior art centerbeam railcar. The risers are slightly declined toward the center partition. Vertical posts which make up the center partition are tapered as they extend upward from the deck of the railcar. When lumber and drywall and loaded onto the declined risers, they xe2x80x9clean intoxe2x80x9d the center. The deck of the car has very little strength between the risers and the risers themselves are not designed to handle especially concentrated loads, since lumber and drywall loads are distributed equally on the risers and along the full length of the car.
Altogether different railcars are utilized for the hauling of steel beams. Short beams are hauled in gondolas or on short bulkhead flat railcars. The longer beams are hauled on very long flat cars. The decks of these cars must be heavily reinforced to allow the loading of the various lengths of steel beams. Unlike lumber loads, loads of steel beams are not generally uniformly distributed. Additionally, the bulkheads utilized in steel-carrying cars must be designed for the extreme impact generated by the movement of the steel beams.
In general, railcars are relatively expensive to purchase and maintain. The profitability of a railroad is determined in substantial part by the efficiency of operation. Efficiency can be increased by minimizing the total number of cars required to meet all of the customers"" needs. Additionally, efficiency can be increased by minimizing the transport of empty cars, whenever possible. Profitability may also be increased by facilitating the ease with which loads are loaded or unloaded from railcars, thus speeding up such operations. Additionally, minimizing the possibility of damage to transported articles in transit or in loading can also affect profitability.
It is one objective of the present invention to provide an improved railcar which can serve multiple functions, including the transportation of relatively light loads such as lumber and drywall, but which can also be utilized to transport relatively heavy loads such as steel beams.
It is an additional objective of the present invention to provide an improved railcar which can be utilized to transport different types of articles, as discussed above, but which increases the ease with which articles are loaded and unloaded from the railcar utilizing overhead cranes, as opposed to requiring the utilization of forklifts.
These and other objectives are achieved as is now generally described. A railcar is provided which may be utilized to transport both relatively light loads (such as lumber and drywall) and relatively heavy loads (such as steel beams), which is made up of a number of components. A generally rectangular base structure is provided. A substantially planar deck covers the upper surface of the generally rectangular base structure. A plurality of rail wheel assemblies are coupled to the lower surface of the base structure and the rail wheel assemblies are adapted for engaging a railroad. A first bulkhead member is coupled to a first end of the base structure and a second bulkhead member is coupled to a second end of the base structure and to the first and second bulkheads. A vertical center partition member is provided in a substantially perpendicular position relative to the base structure. The vertical center partition member is located along a longitudinal centerline relative to the base structure. The vertical center partition member extends between the first and second bulkhead members, and is coupled to the first and second bulkhead members in force-transference therewith. The vertical center partition member provides lateral bending stiffness, vertical bending stiffness, and torsional stiffness.
In the preferred embodiment of the present invention, the vertical center partition member has a substantially uniform width from a lowermost portion which is adjacent the substantially planar deck to an uppermost portion, in order to facilitate loading and unloading operations utilizing overhead cranes. Additionally, in the preferred embodiment of the present invention, the center partition member includes a plurality of tubular vertical posts which provide lateral bending stiffness for the improved railcar. The tubular vertical posts are positioned in particular locations along the longitudinal centerline of the improved railcar, and are secured to the generally rectangular base structure and the substantially planar deck. Additionally, in accordance with the preferred embodiment of the present invention, the vertical center partition member includes a tubular top rail which is located at the uppermost portion of the vertical center partition. The tubular top rail extends between the first and second bulkheads and provides vertical bending stiffness. Additionally, in accordance with the preferred embodiment of the present invention, the vertical center partition member includes a plurality of diagonal brace members extending between the plurality of vertical posts to provide torsional stiffness.
The above as well as additional objectives, features, and advantages will become apparent in the following description.

Flatbed railcar with a center support partition

The Burlington Northern and Santa Fe Railway Company


A system to detect a plurality of elements is proposed. The system includes one or more X-ray sources for transmitting X-rays towards a sample and also includes plurality of photon detectors. An array of crystals are arranged in a curvature with appropriate geometry for receiving a plurality of photon energies emitted from the sample and focusing the photon energy on the plurality of detectors. The plurality of photon detectors are spatially arranged at Bragg angles corresponding to signature photon energies to detect the plurality of elements simultaneously.

The subject matter disclosed herein generally relates to detection of contaminants in fuel and in particular to monitoring and conditioning of gas turbine fuel.
Fuel composition, among other things, influences the corrosion and hence the life of component material in a gas turbine. Fuel may include hydro-carbon based gases and liquids that are directly combusted to produce energy. Elements in the periodic table such as sulfur, sodium, vanadium, potassium, calcium, lead, etc. that may be present as contaminants in the fuel cause degradation of alloy coatings. For example, oxides of sulfur and vanadium may react with other contaminants to form sulfates and vanadates that are corrosive at high temperatures. Typically, the presence of contaminants in fuel, such as sodium, potassium, and vanadium result in deposits from the combustion process that damage the protective surface coating of gas turbine components.
Gas turbine life is affected by corrosion of different components. Fuel composition is a significant contributor to corrosion in gas turbines. The concentration levels of elemental contaminants in the fuel influence gas turbine performance and maintenance in general. Furthermore, contaminants influence degradation of parts of the gas turbine that are exposed to hot-gas including combustors, transition pieces and turbine buckets. Contaminants contained in compressor inlet air, injected steam, and water may also contribute significantly to corrosion. Conventional methods to check for fuel contaminants include manual sampling and testing using a rotating disc emission (RDE) spectrometer. Such methods are prone to corruption of the fuel sample that may arise due to mishandling or poor sampling techniques. Frequent sampling is required at locations where fuels are susceptible to having high contaminant levels. Such frequent sampling is time consuming and labor intensive.
It is desirable to have an online fuel analysis system that provides an ability to track elemental contaminant concentrations in real time. Further, such real time monitoring of fuel would enable timely corrective action and reduce instances of unscheduled maintenance.

Elemental composition detection system and method


The present invention relates to the field of chromatography. More closely, the invention relates to a chromatographic method for purification of plasmaproteins, such as Factor VIII, von Willebrand factor and Factor IX. The chromatographic method is performed on a matrix comprising an inner porous core and outer porous lid surrounding said core.

Blood contains different types of cells and molecules which are necessary for vital body functions, and is therefore collected for therapeutic purposes, eg for blood transfusions. However, it is possible to separate and prepare different fractions from blood, such as red blood cells or cell-free plasma, which enables a more directed therapeutic treatment of medical conditions. Several proteins in plasma can also be further isolated and used for specific therapeutic treatments, eg albumin is used to restore blood volume, immunoglobulins are used for immune deficiencies, and coagulation factors are used for blood coagulation disorders.
Plasma contains proteins of different function, different size, different amount, etc, so there are different methods for purification of the different plasma proteins. The purification processes are often designed to obtain several target proteins from one single starting pool of plasma. The processes typically involve precipitation or chromatography steps or a combination thereof. Chromatography is often used to increase the purity of the target protein and reduce the risk for detrimental side effects. Many plasma proteins exhibit very potent activities, and if present as contaminants, they can cause adverse reactions even at very low levels, when administered to patients.
Collected human plasma is stored frozen, and the initial step in a plasma protein purification process is thawing and pooling of plasma. When thawing at low temperatures, typically 1-6 degrees C., some plasma proteins precipitate and can be collected by eg centrifugation. The collected precipitate is called cryoprecipitate, and can be used as a source of eg coagulation Factor VIII (FVIII) and von Willebrand Factor (vWF). Most of the FVIII in plasma is present as a complex with the large vWF multimers, and the two proteins are therefore often co-purified. The remaining liquid after removal of the cryprecipitate is often referred to as cryodepleted plasma or cryosupernatant, and this can be used as a source of eg albumin, immunoglobulin G (IgG), coagulation Factor IX (FIX).
The purification of many plasma proteins can be challenging. This can depend on the presence of small amounts of contaminants with undesired but potent activity, or that the proteins sometimes lose their activity or gain unwanted activity. For example, the FVIII easily loses activity, and the known methods used for purification are not satisfactory in many respects. Thus, there is a need of improved methods which can be operated at conditions where the proteins retain their activity, in order to obtain plasma products in good yields.

This patent is subject to a terminal disclaimer.

Chromatographic methods for purification of proteins from plasma


A system and method is disclosed for classifying natural language sentences by employing external knowledge to assist in constructing a knowledge base of sentences with a target meaning. The disclosed system and method provide a general sentence classification framework applicable for a knowledge-oriented domain (e.g., domain-specific knowledge). The system and method may be implemented in an intelligent automotive aftermarket assistance tool to assist with the identification of sentences describing specific problems and solutions for car repairs. In addition to the domain adaptability, the system and method is language-independent and could be applicable to any natural written language.

In the field of natural language processing (NLP), information extraction (IE) typically involves the structuring and organizing of information resources from unstructured text. Once complete, IE enables efficient and effective utilization (e.g., searching) of information in downstream applications. IE is generally used to process human language texts by means of natural language processing (NLP) technologies. However, IE may also be used in multimedia document processing to handle automatic annotation and content extraction out of images/audio/video/documents.

System and method for enhancing neural sentence classification