In a magnetic head driving circuit, switching devices are turned on/off in response to a recording signal, thereby inverting a drive current to be applied from direct current power sources to a magnetic head coil. Switching devices to be switched in connection with on/off of the switching devices are connected in parallel with dummy loads connected to the direct current power sources in series. In response to the switching of the switching devices, the magnetic head coil and the dummy load alternately function as a load of each auxiliary coil. Impedances of the dummy loads are set to be equal to the impedance of the magnetic head coil, thereby making the total load of each of the auxiliary coils fixed at any time. Since a balance can be established between a value of a drive current in one direction and that of a drive current in the opposite direction, it is possible to reduce jitter of a recording mark and enable the drive current to suddenly rise and fall.

1. Field of the Invention
The present invention relates to magnetic head driving circuits for driving a magnetic head for recording data on a recording medium, and more particularly, to a magnetic head driving circuit capable of over-writing data on a so-called magneto-optical disc.
2. Description of the Background Art
In recent years, a magnetic field modulating system magneto-optical disc apparatus has been proposed. In such a magneto-optical disc apparatus, data is written through irradiation of a recording portion of a magneto-optical disc with a laser beam of a fixed amount and application of magnetic field to the irradiated portion.
FIG. 4 is a block diagram explaining the principle of such magneto-optical disc apparatus. The magneto-optical disc apparatus shown in FIG. 4 comprises a magneto-optical disc 50 having a vertical magnetization film 51, a lens 52 for picking up a laser beam, a magnetic head 53 and a magnetic head driving circuit 54.
Operation for over-writing the magneto-optical disc 50 will be described. The lens 52 narrows down a laser beam and directs the same to the vertical magnetization film 51 of the magneto-optical disc 50. The irradiation of the laser beam causes the temperature of the vertical magnetization film 51 to exceed a Curie point. The magnetic head driving circuit 54 generates a drive current I in response to input data and supplies the current I to the magnetic head 53. The magnetic head 53 generates a magnetic field H in response to the supplied current I. Thus, the generated magnetic field is applied to the portion whose temperature exceeds the Curie point. As a result, a magnetic pattern corresponding to the input data is recorded on the magneto-optical disc 50.
In order to record data on a magneto-optical disc, however, the current technique requires a magnetic field to be generated which is stronger than that required for an ordinary magnetic disc. It is therefore necessary to bring a large current to a high level or down to a low level at a high speed.
A magnetic head circuit for resolving such problem is disclosed in Japanese Patent Laying-Open No. 63-94406.
FIG. 5 is a circuit diagram showing the magnetic head driving circuit described in Japanese Patent Laying-Open No. 63-94406. With reference to FIG. 5, the magnetic head driving circuit comprises a magnetic head coil 1 having an impedance Lx, auxiliary coils 2 and 4, direct current power sources 3 and 5, switching devices 6 and 7, and a data modulator 8 for modulating input data (recording data) on a predetermined system to generate complementary recording signals S1, S1. The auxiliary coil 2 is connected between a node P which is one end of the magnetic head coil 1, and the direct current power source 3. The auxiliary coil 4 is connected between a node Q which is the other end of the magnetic head coil 1, and the direct current power source 5. Each of the auxiliary coils 2 and 4 have an impedance Ld (Ld>>Lx) larger than the impedance Lx of the magnetic head coil 1.
The switching device 6 is connected between the node P and a ground terminal GND and is turned on/off in response to the recording signal S1. The switching device 7 is connected between the node Q and the ground terminal GND and is turned on/off in response to the recording signal S1.
FIG. 6 is a diagram showing operation of the magnetic head driving circuit shown in FIG. 5. With reference to FIG. 6, (a) is a waveform diagram of the recording signal S1, (b) a waveform diagram of the recording signal S1, (c) a waveform diagram of the charging current I.sub.1 flowing through the auxiliary coil 2, (d) a waveform diagram of the charging current I.sub.2 flowing through the auxiliary coil 4, (e) a waveform diagram of the drive current Ix flowing through the magnetic head coil 1, (f) shows a load impedance of the auxiliary coil 4 and (g) shows a load impedance of the auxiliary coil 2.
With reference to FIGS. 5 and 6, operation of the magnetic head driving circuit shown in FIG. 5 will be described.
First, the data modulator 8 modulates recording data to generate two recording signals S1 and S1 complementary to each other. The recording signal S1 is applied to the switching device 6, while the recording signal SI is applied to the switching device 7. When the switching device 6 is turned on in response to the recording signal S1 (logical high level) and the switching device 7 is turned off in response to the recording signal S1 (logical low level), the circuit shown by the solid line in FIG. 5 is established wherein the charging current I.sub.l for charging the auxiliary coil 2 flows from the direct current power source 3 to the ground terminal GND through the auxiliary coil 2 and the switching device 6. At this time, the charging current I.sub.2 for charging the auxiliary coil 4 flows from the direct current power source 5 to the ground terminal GND through the auxiliary coil 4, the magnetic head coil 1 and the switching-device 6. Thus, the magnetic head coil 1 is supplied with the drive current I.sub.X from the node Q toward the node P.
On the other hand, when the signals S1 and S1 are inverted to turn on the switching device 7 and turn off the switching device 6 as indicated by dotted lines in FIG. 5 (see FIGS. 6 (a) and (b)), the charging current I.sub.2 for charging the auxiliary coil 4 flows from the direct current power source 5 to the ground terminal GND through the auxiliary coil 4 and the switching device 7. At this time, the charging current I.sub.1 for charging the auxiliary coil 2 flows from the direct current power source 3 to the ground terminal GND through the auxiliary coil 2, the magnetic head coil 1 and the switching device 7. The drive current I.sub.X therefore flows to the magnetic head coil 1 from the node P toward the node Q.
In response to on/off of the switching devices 6 and 7, the load of the auxiliary coil 2 (see FIG. 6 (g)) and the load of the auxiliary coil 4 (see FIG. 6 (f)) attain the impedance Lx of the magnetic head coil or 0.
The relationship between said charging currents I.sub.1 and I.sub.2 is described in the above-mentioned Japanese Patent Laying-Open No. 63-94406, wherein the inductance of the auxiliary coils 2 and 4 is denoted by La and the inductance of the magnetic head coil 1 by Ln to establish the following equation. ##EQU1##
Since the relationship of the impedances is expressed as Ld>>Lx, the relationship of La>>Ln is also established, resulting in I.sub.2 .apprxeq.I.sub.1. As is seen from the above equation, the relationship between I.sub.1 and I.sub.2 includes no factor of time. As a result, it is possible to increase an inversion rate of a drive current Ix by setting the impedances of the auxiliary coils 2 and 4 to be larger than that of the magnetic head coil 1. In addition, with Ld>>Lx, Lx is substantially 0, comparatively so that load fluctuation of the auxiliary coils 2 and 4 is negligible.
However, to increase the frequencies of the recording signals S1 and S1 in order to increase the data recording rate, the above-mentioned impedance Ld should be as small as possible. As the impedance Ld is decreased, Ld is no longer negligible with respect to Lx. In other words, load fluctuation occurs.
This is followed by imbalance between the charging currents I.sub.1 and I.sub.2 of the respective auxiliary coils 2 and 4, causing difference as shown in FIGS. 6 (c) and (d). Zero-cross points of the drive current I.sub.x therefore shift and the drive current I.sub.X of the magnetic head coil 1 have different values at a positive level and a negative level, so that jitter of the recording mark is increased to deteriorate the reliability of reproduced data.
The above-described problem becomes particularly conspicuous in the following case. That is, it is a case where a generally known and employed NRZI recording system (Non-return to Zero Inverse) of 2-7 RLL code (2-7 Run Length Limited) is used as a modulation system for recording/reproduction in a magneto-optical disc apparatus. While such system has an advantage of increasing a recording density, it also has a disadvantage that a recording signal in which recording bits are modulated includes a large amount of direct current components. It is therefore impossible to avoid the above-described problem when a recording signal of the above-described system is input to a conventional magnetic head driving circuit.
FIG. 7 shows a bit arrangement of recording data based on the above-described 2-7 RLL code. The 2-7 RLL code includes two to seven "0" between "1" and "1". Modulation of the code by a data modulator of the NRZI system generates recording signals S1 and S1 including a large amount of direct current components as shown in FIGS. 6 (a) and (b).
FIG. 8 is a circuit diagram of another magnetic head driving circuit disclosed in above-mentioned Japanese Patent Laying-Open No. 63-94406. With reference to FIG. 8, the magnetic head driving circuit comprises a magnetic head coil 15, switching devices 11, 12, 13 and 14, a direct current power source 17 and an auxiliary coil 18. The relationship of the impedances between the auxiliary coil 18 and the magnetic head coil 15 is the same as that of the case shown in FIG. 5. The switching devices 11 and 14 both turn on/off in response to the recording signal S1. The switching devices 12 and 13 both turn on/off in response to the recording signal S1. The NPN transistor shown in FIG. 9 is used for the switching devices 11-14. Nodes C11 and E11 of FIG. 8 represent a collector and an emitter of the switching device 11 and nodes C13 and E13 represent a collector and an emitter of the switching device 13. The NPN transistor can be replaced by the PNP transistor shown in FIGS. 10 or various devices such as FET (not shown).
FIG. 11 is a diagram illustrating the operation of the magnetic head driving circuit shown in FIG. 8. With reference to FIG. 11, (a) and (b) show waveform diagrams of the signals S1 and S1. (c), (d), (e) and (f) are waveform diagrams of the voltages of the collector C13, the emitter E13, the collector C11 and the emitter E11, respectively. FIG. 11(g) shows a load impedance of the auxiliary coil 18. The broken lines of (d) and (f) show base voltages of the switching devices 13 and 11.
With reference to FIGS. 8 and 11, operation of the magnetic head driving circuit shown in FIG. 8 will be described. First, recording data is modulated to generate signals S1 and S1. The switching devices 12 and 13 turn on in response to the signal S1 (high level), while the switching devices 11 and 14 turn off in response to the signal S1 (low level). Conversely, when the signal S1 is at a low level and the signal S1 is at a high level, the switching devices 12 and 13 turn off, while the switching devices 11 and 14 turn on.
That is, when the switching devices 12 and 13 turn on (see FIG. 11 (a)) and the switching devices 14 and 11 turn off (see FIG. 11 (b)), for example, as shown in FIG. 8, the charging current of the auxiliary coil 18 flows from the direct current power source 17 to the ground terminal GND through the auxiliary coil 18, the switching device 13, the magnetic head coil 15 and the switching device 12. As a result, the drive current I.sub.X is supplied to the magnetic head coil 15 from the node Q toward the node P.
Conversely, when the switching devices 14 and 11 turn on and the switching devices 12 and 13 turn off, the charging current of the auxiliary coil 18 flows from the direct current power source 17 to the ground terminal GND through the auxiliary coil 18, the switching device 11, the magnetic head coil 15 and the switching device 14. As a result, the drive current I.sub.X is supplied to the magnetic head coil 15 from the node P toward the node Q.
In this related art, the load of the auxiliary coil 18 is fixed (equal to the impedance Lx of the magnetic head coil 15) as shown in FIG. 11 (g), in response to on/off of the switching devices 12 and 13 and the switching devices 14 and 11. The problem of load fluctuation in the magnetic head driving circuit of FIG. 5 is therefore resolved.
In the magnetic head driving circuit in FIG. 8, however, the voltage waveforms of the collectors C.sub.13 and C.sub.11 and those of the emitters E.sub.13 and E.sub.11 have a large spike-shape because of the current flowing through the auxiliary coil 18 and the magnetic head coil 15 immediately after on or off of the switching devices 12 and 13 and the switching devices 14 and 11.
Since the voltage of the emitter E.sub.13 and the voltage of the emitter E.sub.11 become higher than the base voltages (indicated by X in FIG. 11) because of the spike-shaped waveform, the switching device 13 remains off (not shifted to an on state) immediately after the base voltage is inverted from a low level to a high level, and conversely, the switching device 11 remains on (not shifted to an off state) immediately after the base voltage is inverted from a high level to a low level (Y in FIG. 11).
The drive current I.sub.X of the magnetic head is therefore slow to rise and fall. This is because of the circuit structure wherein the switching devices 13 and 11 are placed between the auxiliary coil 18 and the magnetic head 15.
The use of the PNP transistor shown in FIG. 10 as the switching devices 12 and 13 and the switching devices 14 and 11 of FIG. 8 changes the waveforms of FIG. 11 to those shown in FIG. 12. With reference to FIG. 12, C.sub.13 and C.sub.11 are voltage waveforms of the collectors of the switching devices 13 and 11, respectively, and E.sub.13 and E.sub.11 are voltage waveforms of the emitters of the switching devices 13 and 11, respectively. B.sub.13 ' and B.sub.11 ' are voltage waveforms of the bases of the switching devices 13 and 11, respectively.
Description will now be made of generation of spike noise and delay in switching response in a case where a PNP transistor is used as a switching device.
Similarly to the case of the NPN transistor, the voltage waveforms of the collectors C.sub.13 and C.sub.11 and those of the emitters E.sub.13 and E.sub.11 have a large spike-shape because of the current flowing through the auxiliary coil 18 and the magnetic head coil 15 immediately after on or off of the switching devices 12 and 13 and the switching devices 14 and 11.
Since the voltage of the collector C.sub.13 (see FIG. 12 (c)) and the voltage of the emitter C.sub.11 (see FIG. 12 (e)) become higher than the base voltages because of the spike-shaped waveform, the switching device 11 remains on (not shifted to an off state) immediately after the base voltage B.sub.13 ' attains a high level (see Z in FIG. 12).
Therefore, the drive current I.sub.X of the magnetic head is slow to rise and fall. This is also because of the circuit structure wherein the switching devices 13 and 11 are located between the auxiliary coil 18 and the magnetic head coil 15. Although the description is made of NPN or PNP transistor by way of example of the switching devices 12 and 13 and the switching devices 14 and 11, it is obvious that the same problem occurs even if a switching element of FET or the like is used.
A magnetic head circuit having improved rise and fall characteristics of a drive current to be applied to a magnetic head coil is disclosed in Japanese Patent Laying-Open No. 63-244402.
FIG. 13 is a schematic circuit diagram of the magnetic head driving circuit disclosed in said Patent Laying-Open No. 63-244402. The magnetic head driving circuit shown in FIG. 13 differs from that of FIG. 8 in that a timing generator 19 is provided for generating signals S2, S3, S4 and S5 for-controlling on/off timing of the switching devices 11-14 in response to the recording signal S1. The signal S2 is applied to the switching device 12, the signal S3 to the switching device 11, the signal S4 to the switching device 14 and the signal S5 to the switching device 13.
FIG. 14 is an output waveform diagram of each circuit of the magnetic head driving circuit shown in FIG. 13. With reference to FIG. 14, (a) shows a waveform diagram of the recording signal S1, (b) shows that of the signal S2, (c) shows that of the signal S3, (d) shows that of the signal S4, (e) shows that of the signal S5 and (f) shows a waveform of the drive current I.sub.X.
Operation of the magnetic head driving circuit shown in FIG. 13 will be described.
When the direction of the drive current Ix is changed to flow from the node Q toward the node P, the signal S5 rises prior to falling of the signals S3 and S4. A time difference between the falling of the signals 3 and 4 and the rising of the signal S5 is represented as .DELTA.t.sub.1.
The switching device 11 and the switching device 14 change from on to off in response to the change of the signal S3 from a high level to a low level and the change of the signal S4 from a high level to a low level, respectively. The switching device 13 is turned on in response to the signal S5 which has risen earlier by a predetermined time .DELTA.t.sub.1 than the falling of said signals S3 and S4.
Conversely, when the drive current Ix is changed to flow from the node P toward the node Q, the signal S3 is brought to high prior to falling of the signals S2 and S5. A time difference between the falling of the signals S2 and S5 and the rising of the signal S3 is represented as .DELTA.t.sub.2. The switching device 11 therefore turns on before the switching devices 13 and 12 turn off.
As a result, a sufficient charging current is supplied to the auxiliary coil. When the switching device is switched, a charge generated by counter electromotive force of the coil causes the drive current to be applied to the magnetic head coil 15 to suddenly rise and fall.
However, increasing the frequency of the recording signal S1 (increasing a data transmission rate) requires the above-described .DELTA.t1 and .DELTA.t2 to be considerably small. As a result, the auxiliary coil cannot be fully charged, so that a time required for the drive current for the magnetic head coil to rise and fall cannot be reduced.
The foregoing problems of the related art are summarized in the following (1) to (3).
(1) Values of a current to be applied to the magnetic head coil lose balance between positive and negative. In other words, a gap is generated between a value of the current to be applied to the coil in one direction and that of the current to be applied to the same in the opposite direction. As a result, jitter of the recording mark is increased.
(2) Even if the level of the recording signal (base voltage) is switched, the switch remains off immediately after that, whereby the drive current to be applied to the coil is caused to rise and fall slowly.
(3) Increase of a rate for recording data is followed by a reduction of charging time, resulting in insufficient charging of the auxiliary coil. It is therefore impossible to cause the drive current to be applied to the coil to suddenly rise and fall.
Thus, it is difficult for any of the above described conventional systems to record data of such as 2-7RLL code at a high speed.

Magnetic head driving circuit with impedance elements to balance auxiliary coil loads


A cementitious slurry comprising microfine ground blast furnace slag and normally ground blast furnace slag. A microfine ground blast furnace slag is made of composition having a blaine specific surface area between 8,000 and 20,000 cm.sup.2 /g. By normally ground is meant slag compositions having a surface area of less than 8,000 cm.sup.2 /g. Such cementitious compositions have utility in construction, road building, and cementing wellbores.

The present invention relates to slag cement, and more particularly to drilling and cementing boreholes.
Grouting with fine ground slag cement is known. Such grouting is disclosed in Clarke, U.S. Pat. No. 4,761,183 (Aug. 2, 1988) and Clarke, U.S. Pat. No. 5,106,423 (Apr. 21, 1992). The '423 patent also discloses petroleum as an area of utility for the cementitious slurries described in the invention.
The teaching of Clarke follows conventional wisdom that the advantages flowing from the use finely ground hydraulic materials can justify the grinding expense. However, the difficulty of such grinding is quite great. The particle sizes of even normally ground hydraulic materials are generally in the micron range. Relative to slag broadly, Clarke '423 teaches that less than 3%, preferably less than 1.5%, and most preferably, no particles are larger than 7.8 microns in diameter should be present.


This specification describes a system and method that can offer, among other advantages, a technique for resource assignment that involves obtaining a group of resources, repeatedly selecting a resource from the group of resources until a resource that is available is selected, and associating a client or process with that resource. An example of a method according to the technique includes obtaining a group of VLANs for assignment to a client based on client identity, selecting a first choice from the group of VLANs, selecting a next choice from the group of VLANs if the first choice is unavailable, and connecting the client to the selected VLAN. The client identity may include, by way of example but not limitation, a MAC address, an SSID, or some other known or convenient way to identify the client. A system constructed according to the technique may include, by way of example but not limitation, memory, a resource group name decoder, a value calculator, an index calculator, and a selector. The memory may include, for example, a resource name buffer, an identity buffer, a result buffer, a resource count buffer, a resource name array, and a selected resource buffer.

The field relates to communications networks in which subnetworks are employed.
If the number of users of a network is very large, the performance may be degraded by broadcast traffic, such as ARP and DHCP requests. Each device on the network generates a certain amount of broadcast traffic, which every other device must receive and examine to at least some degree, whereby the burden of broadcast processing rises as the square of the number of devices on the network. The degradation due to this effect can become significant even when the network traffic is well within the capacity of the physical transmission medium.
A common solution, described by Mogul and Postel (RFC 950, which is incorporated by reference) is to divide the network into subnets. Subnets can be implemented physically by using separate local-area networks (LANs), or logically by partitioning into virtual LANs (VLANs) as in IEEE 801.1Q, or by a combination of the two techniques. Any particular user's impact is then limited to the specific subnetwork to which the user is assigned. However, in the context of administering a large network, this solution still poses problems, related to the method of assigning users to subnets.
A simple method would be to use the same technique for wireless users as has historically been used for wired users, namely, determining the subnet from the physical location or port through which the user accesses the network. A known disadvantage of this method is that a mobile user who moves across a subnet boundary will lose connectivity at the network layer (Layer 3 of the OSI model). This method may therefore not be optimal for applications that require continuous connectivity while a user moves, e.g. IP telephones. Even if the user is not in motion, location-based subnet assignment may not be optimal if the user is close to a boundary between two wireless coverage areas that use different subnets, because fluctuations in the radio signal could cause the user's equipment to alternate between the coverage areas, losing connectivity each time.
Although location-based subnet assignment can (with the above-noted disadvantages) accomplish one purpose of subnets by reducing the number of users per subnet, it thwarts another important purpose of subnets, namely the separation of traffic by access privilege.
An alternative to location-based subnet assignment is to base the subnet assignment on the user's identity. Identity-based VLAN assignment is implemented in current products from, e.g., Trapeze Networks. The user's VLAN assignment is considered to be an authorization attribute of the user, and so an administrator configures it as part of the user's AAA information in an AAA server, which is typically a Radius server. This administrative effort is justified, and identity-based authorization is especially advantageous, if there is a managerial or security motivation for placing particular users into particular subnets. However, if the number of users is so large as to motivate dividing the network into subnetworks, then the administrative burden of assigning a subnet to each user will also be proportionately large.
RFC 2904 due to Vollbrecht, et al., which is incorporated herein by reference, shows frameworks for authorization in the typical context of AAA (Authentication, Authorization, and Accounting) for a network. This authorization framework is applicable to wireless or wired users. However, in the case of wireless users, the operations described in RFC 2904 must be preceded by other operations specific to establishing a wireless connection. For instance, in 802.11 wireless networks, these preliminary operations include an 802.11 association request from the wireless client device, identifying the client device by hardware (MAC) address. Typically the user's name, password, and/or other AAA parameters are exchanged after the association request has been accepted.
The 802.11 association request also includes a Service Set ID (SSID) that names a wireless service to which the client wishes to connect. If the service equipment supports multiple subnets or VLANs, a common (although not mandatory) implementation choice is to identify an SSID with each VLAN. In that method, the user's request to associate through a given SSID implies that the subsequent authorization processing should connect the user to the VLAN corresponding to that SSID. In that case there is no explicit authorization request from the user, although again, authorization parameters can be obtained from the AAA server as a side effect of authentication.
These and other issues are addressed, resolved, and/or ameliorated using techniques described herein.


A thermal imager referencing system comprises two rotating cranks in the form of discs (7, 8) each pivotally attached to connecting member (9). The discs (7, 8) are rotated at a constant speed causing two mirrors laterally displaced along connecting member (9) to intercept an optical path X of a thermal imager associated with the referencing system. Each rotation through 360 degrees of the discs (7, 8) causes each mirror to pass once through the optical path, the mirror surfaces being respectively arranged to cause a linear array of detector elements (not shown) of the thermal imager to view alternately thermo-electric devices (14, 16), which are at different temperatures, during the flyback time associated with the thermal imager. The referencing system enables processing means of the thermal imager to normalize the detector array, compensating for DC offset and differences in gain between different elements of the detector array. The referencing system is of a particularly compact design and minimizes the effect of any temperature variations across the surfaces of the Peltier on the normalization process.

The present invention relates to a referencing system for an array of detector elements of a thermal imager and in particular to a referencing system for use with a thermal imager having a linear array of detector elements over which a viewed scene is scanned.
In most thermal imager systems it is necessary to process the signal received from the output of an array of detector elements of the imager, in order to compensate for DC offset in the output between different elements of the array, and to compensate for differences in responsivity (gain) between the elements. This is referred to as "normalizing" the detector array.
DC offset between elements of a detector array can be compensated for by exposing all the elements to a thermal reference source of uniform temperature. Certain types of detector arrays such as pyro-electric arrays require exposure to a uniform field in order to function, for they rely on the change of a charge which occurs between being exposed to a closed, or shuttered, field and being exposed to the scene to be viewed. The exposure to the shuttered field compensates every frame for any DC offset. With such pyro-electric type detectors, the difference in gain between the elements can be compensated for periodically by exposing the detector elements to a uniformly intense open field, and this may be done once only in the life of the detector during the manufacturing process.
With photovoltaic type detectors there is no requirement to shutter the detector array and therefore there is no inherent DC offset compensation, but normally both DC offset and non-uniformity gain characteristics have to be compensated for. This can be achieved by exposing the detector array to uniform light and dark fields during an initial calibration process, however the DC offset between elements is dependent on the mean temperature of the viewed scene. The gain characteristics of the elements are also unlikely to be linear and therefore any compensation for the difference in gain characteristics will vary in dependence on the mean temperature of the viewed scene. In certain applications it is preferable that differences in offset and gain characteristics of the detector elements of photovoltaic detectors are compensated for in use.
Many photovoltaic imaging systems employ a linear array of detector elements over which the image is scanned. With such a system there will normally be a "flyback" period when the scanning mechanism returns to its starting position. Even with a scanning mechanism employing a multi-faceted polygonal mirror surface where the scanner itself does not have a flyback period, because the final image generated is normally to be a TV-type display which itself has a flyback period, there is a period in which information is not read out from the detector, or the information read out is not utilized in the final display. The "flyback" period can conveniently be utilised to normalize the elements of the array by exposing them to two uniform thermal reference sources at different temperatures.
U.S. Pat. No. 4 948 964 discloses a method for normalizing a photovoltaic detector array. This is achieved by exposing the detector array to a uniform thermal reference source. The detector array is exposed to the reference source by a scanning minor surface which is inserted in the optical path of the detector array during the flyback period. The mirror surface is arranged such that during the flyback period the detector array views a thermo-electric cooler at a uniform temperature. The mirror surface itself forms a radial sector of a disc rotated about an axis, and comprises two portions of different reflectivities. The two portions of different reflectivities enable two reference temperatures to be observed, the highly reflective portion exposing the detector array to a temperature approximately equal to that of the thermo-electric cooler, while the partially reflective portion exposes the detector array to a temperature between the temperature of the thermo-electric cooler and the temperature of the mirror surface itself.
The problems with the above described method are that the scanning mirror surface has to be sufficiently large in order to ensure that the whole detector array is irradicated by the thermo-electric cooler and that it is difficult to control the range of the two reference sources, for the range of the partially reflective mirror surface will depend upon the temperature of the mirror surface itself, which in turn will depend upon the temperature of the working environment. It is an aim of the present invention to provide an improved referencing system for a thermal imager.


A device is provided for connecting pipe parts between two compartments of a filtration unit for water of a swimming pool. The filtration unit has a filtration compartment submerged in the water and equipped with at least one filtration means and a pumping compartment situated outside of the swimming pool and equipped with at least one suction and return pump. The compartments are connected by a common part that straddles the walls of the swimming pool. The filtration means and pump or pumps are connected in combination with suction and return pipe parts, which have one part situated in the filtration compartment and one part situated in the pumping compartment. At the common connecting part, watertight connecting members are positioned between the suction and return pipe conduit parts, whose thickness is less than the diameter of the various pipe parts.

The invention relates to the technical field of filtration systems for swimming pools.
More specifically, the invention relates to the compact water filtration units used in swimming pools. These units comprise, in a known way, a "filtration" compartment and a "pumping" compartment. The filtration compartment is designed to be submerged in the water of the swimming pool. This compartment houses one or more filtration means of any appropriate known type. The pumping compartment is situated on the outside of the swimming pool. It is usually buried, and has one or more pumps for sucking the water in and returning it, as indicated in the rest of this description. The pumping and filtration compartments are connected by a common part which usually straddles the walls of the swimming pool, whatever its specific design. This part of the overall filtration unit has the shape, very approximately, of an upside-down staple. Examples of this type of filtration unit can be found in the teachings of patents FR 97.01642, FR 98.03790 and FR 99.12856.
In essence, the filtration means, whatever its particular design, is connected, by pipe elements, to the pump or pumps installed in the pumping compartment. More particularly, these pipe elements are connected to the suction intake of the pump. Other pipe elements are connected to the pump's return outlet where the filtered water is returned to the swimming pool by means of for example nozzles on a part of the filtration compartment.
Clearly, the suction and return pipe systems are made up of several elements connected by elbows or the like to form the connection between the filtration compartment and the suction compartment. For reasons of ease of installation and to keep costs down, these pipe elements are of round section and advantageously made of PVC, conforming with standard components as widely available in the trade. Specifically, the use of this kind of round-section pipe element keeps costs down and enables different types of connection to be made.
Because of the need to make a circuit to carry the water between the filtration compartment and pumping compartment, the suction and return pipes are also present in the common connecting part between the two compartments. In this area the suction and return pipes are usually placed side by side in a horizontal plane.
As a result, these round-section pipes occupy a certain height, so that the common connecting part appears above the edge of the swimming pool. The same is also true of the filtration and pumping compartments.
In other words, the filtration unit as a whole, in the prior art, must project high enough to allow the suction and return pipes to pass across. This excess height is not always very appealing to the eye and can interfere with the integration of the complete filtration unit in the coping and areas around the pool.


A low temperature coefficient (TC) voltage output circuit compensates for the TC of a base circuit""s output voltage with a compensation circuit that includes first and second current sources with different TCs. The differential between the current sources is applied to a voltage drop circuit that generates a temperature dependent compensation voltage with a TC of opposite polarity to the TC of the base circuit""s output. To provide compensation over a desired temperature range, the two current sources are set equal to each other at one temperature within the range, and the compensated voltage output is trimmed at another temperature within the range to the desired output value. The result is a compensated voltage, with a TC of opposite polarity to that of the base circuit""s output, which combines with the base circuit output to yield a low TC compensated output. The compensation scheme is particularly useful for voltage references.

1. Field of the Invention
This invention relates to low temperature coefficient voltage output circuits, and more particularly to providing temperature compensation to a base circuit which produces a preliminary output voltage having a temperature coefficient of known polarity.
2. Description of the Related Art
Voltage reference circuits provide a fixed voltage for purposes such as regulated power supplies and comparison with other voltages. It is important that the output voltage of the reference circuit be made temperature invariant, to the extent practical. This is typically done by measuring the reference""s output voltage at high and low temperatures, and then trimming the circuit to compensate for changes in the output voltage between the two measurement temperatures.
In practice, multiple voltage references in integrated circuit (IC) form are typically provided on a single wafer, the voltage measurements at the high and low temperatures are taken at the wafer level, and the individual reference circuits are then trimmed to reduce their temperature dependency, also at the wafer level. Other circuits also require some form of temperature compensation to maintain a substantially temperature invariant voltage level. One example is the offset voltage for an operational amplifier.
There are several problems with this approach. First, the wafers are typically held on a chuck, and the chuck temperature is commonly directly sensed to obtain an indication of the wafer temperature. This requires that the chuck temperature at which the voltage is read be accurately known, which is difficult to do in a production environment. Furthermore, although the chuck temperature is generally close to that of the wafer, the two temperatures are usually not exactly equal, which leads to further inaccuracies. While the wafer temperature can be read directly, this is expensive to do. Also, it is necessary to keep track of which voltage and temperature measurements go with which die on a given wafer, and among the dies of different wafers. Again, this is difficult to do in a production environment.
The present invention seeks to provide a voltage output circuit with a low temperature coefficient (TC), and an associated temperature compensation method which eliminates the need for both accurate temperature measurement, and for keeping track of the different dies and wafers and their associate voltage and temperature measurements.
These goals are achieved with a voltage output circuit that includes a base circuit which produces a preliminary output voltage having a TC of one polarity, and a compensation circuit having a pair of current sources with different TCs that are connected to compensate for the TC of the base circuit""s output voltage (Vo) so as to yield a compensated Vo with a lower TC than the preliminary Vo TC. The differential between the currents of the two current sources is transformed to a voltage drop which has a TC of opposite polarity to the TC for the base circuit""s Vo. The voltage drop is combined with the base circuit Vo to yield the compensated Vo.
In a preferred embodiment, the voltage drop circuit is implemented with a resistor connected to receive a current that varies with the differential between the two current sources. The resistor produces a compensation voltage with a TC that approximates, but is of opposite polarity to, the preliminary Vo TC.
To provide a compensated Vo over a predetermined temperature range, the current sources are first trimmed at one temperature level within the range, preferably at one end of the range, so that they are substantially equal in absolute value and thereby cancel, producing zero compensation voltage. Then, at another temperature within the range, preferably at the opposite end of the range, the voltage drop resistor is trimmed to set the compensated Vo at the desired value.
One of the current sources can have a positive TC and the other a negative TC, or the current sources can both have positive or negative TCs, so long as the TC of one source differs from that of the other in a direction and by an amount that produces a compensation voltage of the desired polarity and magnitude. In the case of a voltage reference circuit, the compensated Vo is amplified by an output buffer amplifier. The amplifier is trimmed to produce a desired reference voltage at the first temperature setting, at which the current sources are set equal, and continues to provide the same or a close reference voltage as the temperature varies.
These and other features and advantages of the invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings.

Low temperature coefficient voltage output circuit and method


A multi-blade ice-skate footwear includes a foot-retaining section with a substantially planar bottom surface, a first blade adjustably connected to an anterior portion of the bottom surface, and second and third blades adjustably connected to a posterior portion of the bottom surface and spaced from the first blade respectively. The ice-skate footwear includes a mechanism for selectively biasing the first blade along a first reciprocating linear path while simultaneously biasing the second and third blades along second and third reciprocating linear paths respectively.

1. Technical Field
This invention relates to ice-skating footwear and, more particularly, to a triple-blade ice-skating footwear for assisting a novice user to maintain balance and stability during ice-skating procedures.
2. Prior Art
The typical ice skate known in the prior art generally includes a single narrow blade extending longitudinally and depending subjacent from a shoe or boot secured to the foot of the skater. Although this construction suffices for a great number of skaters, it is well recognized that many individuals are not capable of using and enjoying the typical single blade skate. The single blade skate establishes a very narrow support base upon which a comparatively wide load must be supported. As a result, there is an inherent instability in this overall arrangement. This instability can be overcome by individuals having relatively strong and rigid ankle joints, as well as a keen sense of balance. For an individual lacking these attributes, skating can be a perilous and unpleasant pastime.
There are known in the prior art various skate constructions which attempt to overcome the deficiencies of the single blade skate. These constructions generally comprise various forms of double blade skates in which a pair of longitudinally extending blades is laterally spaced to provide a wider base of support. However, the effect of enhanced stability is created only when both of the blades are in contact with the ice. Due to the fact that the pair of blades is generally not widely spaced apart, an individual having weak ankles will cause the skate to roll about a longitudinal axis, resulting in only one blade contacting the ice. Thus the skater still will experience severe problems in balance and control. Based on the above mentioned needs, it would be advantageous to provide a means for assisting a beginning skater to skate confidently and safely.
U.S. Pat. No. 3,695,609 to Rothe discloses a skating aid formed by bending two base sections to form a runner and a vertical support section. The vertical support sections are joined to fix the runners apart and generally coextensive. A handle is attached to the vertical support section and can be formed integrally therewith. Wheels can be attached to the runners. The aid is useful in training persons to ice skate or roller skate. Unfortunately, this prior art example is not customized to help students learn to skate based on the standard design of the ice skates themselves.
U.S. Pat. No. 4,407,522 to Suroff discloses a energy saving ice skate attachment device for attachment to an ice skate, or the like, also suitable for training skaters, includes an elongated frame with a pair of outboard blades having its edge portion coplanar with the blade of the ice skate, is clamped to the ice skate by means of a U-shaped clamping device which affixes the frame of the attachment device to the shoe supporting post of the ice skate. Resilient means are disposed between the horizontal portion of the attachment device frame and the underside of the ice skate shoe, thereby permitting at least two blades to contact the surface of the ice even during turns, thereby reducing the energy needed to utilize the skates. Unfortunately, this prior art example does not provide the balance and confidence needed to develop ice-skating skills.
U.S. Pat. No. 4,418,928 to Cox discloses a ice skate that provides exceptional lateral stability and includes a boot having a sole plate extending longitudinally between the toe portion and the heel portion of the boot. A pair of adjustable shock absorbing mounting assemblies is joined to the toe portion and the heel portion of the sole plate. A pair of ice engaging members is provided, each secured to one of the shock absorber mounting assemblies. The ice engaging members extend transversely with respect to the longitudinal axis of the boot to provide high lateral stability. Projecting downwardly from the lower surfaces of the ice engaging members is a plurality of laterally spaced, longitudinally extending ribs which are adapted to slide on ice. Unfortunately, this prior art example is not customized to help students learn to skate based on the standard design of the ice skates themselves.
Accordingly, the present invention is disclosed in order to overcome the above noted shortcomings. The device is convenient and easy to use, lightweight yet durable in design, and designed for assisting a novice user to maintain balance and stability during ice-skating procedures. The multi-blade ice-skate footwear is simple to use, inexpensive, and designed for many years of repeated use.

Triple-blade ice skating footwear and associated method


An indoor automatic aquaculture system has an indoor breeding pond constructed in a stepwise manner for breeding aquatic or marine products in a staged-breeding approach to increase breeding density and reduce required space. Breeding water is processed in advance by a recirculating water treatment system and water quality is constantly monitored by a water quality monitor and control system to maintain the breeding water at the optimum condition. A movable feed dispensing control system is located above the breeding pond for dispensing feeds evenly thereby to increase breeding survival rate, improve breeding yield and better control breeding product quality.

The present invention relates to an aquaculture system and particularly an indoor aquaculture system that is capable of automatically monitoring water quality, automatically replenishing breeding water and automatically dispensing feeds.
Traditional aquaculture systems generally utilize groundwater and adopt outdoor breeding to grow aquatic or marine products. As ground water or sea water being pumped to the breeding ponds has low oxygen content and a great amount of microbes, the breeding aquatic or marine products tend to die easily. Moreover, pumping huge amount of ground water often makes land subsidence and causes erosion of the breeding ponds. In recent years, foul breeding environments and radical weather changes have spawned various viruses that seriously threaten living conditions of the breeding creatures (such as fishes, shrimps, etc.). As a result, survival rate of the breeding creatures drops significantly. In order to resolve the impact of aforesaid deteriorating external environments and ground water to the breeding businesses, indoor breeding and recirculating water aquaculture systems have gained greater awareness and attention these days, and have become hotly pursued research and development subjects.
The primary object of the invention is to provide an indoor breeding and divided-pool breeding method to overcome the harmful effect resulting from external environments and to improve breeding survival rate.
Another object of the invention is to provide a high density aquaculture system to increase breeding yield.
A further object of the invention is to provide an automatic aquaculture system to facilitate control of breeding water quality and dispensing of feeds in a constant time and quantity manner.
To achieve the foregoing objects, the indoor automatic aquaculture system of the invention mainly includes a set of breeding pond, a recirculating water treatment system, a plurality of feed dispensing apparatus, an external system and an automatic monitor and control system. Breeding creatures are bred in the indoor stepwise breeding pond and are grown is staged manner to increase breeding density and reduce space required. Breeding water is processed in advance by the recirculating water treatment system. Water quality and condition in the breeding pond is constantly monitored by a water quality monitor and control system and is maintained at the optimum condition. The automatic feed dispensing apparatus are movably located above the breeding pond to evenly dispense feeds. By means of aforesaid arrangements, breeding survival rate can be increased and breeding yield can be improved, and breeding water quality can be better controlled.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.


The invention relates to a bar code reading apparatus of the sensing for a bar code along a scanning direction, comprising a light source to produce a transmitted light beam and a diaphragm to restrict the cross-section of the transmitted light beam, wherein the diaphragm has a diaphragm aperture, the boundary of which has four adjoining sections, of which two sections lie opposite to one another and extend substantially transverse to the scanning direction (transverse sections), and of which two sections lie opposite to one another and extend substantially along the scanning direction (longitudinal sections). In order to compensate for diffraction effects of the transmitted light beam, the boundary of the diaphragm aperture has at least one compensatory projection at at least one transverse section, with the compensatory projection projecting as an intermediate extremity into the diaphragm aperture with respect to this cross-section in the direction towards the oppositely disposed cross-section

1. Field of the Invention
The present invention relates to a bar code reading apparatus for the sensing of a bar code along a scanning direction, comprising a light source to produce a transmitted light beam and a diaphragm to restrict the cross-section of the transmitted light beam, wherein the diaphragm has a diaphragm aperture, the boundary of which has four adjoining sections, of which two sections lie opposite to one another and extend substantially transverse to the scanning direction (transverse sections), and of which two sections lie opposite to one another and extend substantially along the scanning direction (longitudinal sections).
2. Description of the Prior Art
Such bar code reading apparatuses serve for the scanning of bar codes. The scanning direction corresponds to the direction of relative movement between the transmitted light beam and the bar code. A relative movement of this kind can, for example, be achieved when the bar code reading apparatus has a deflection unit, by which the transmitted light beam is periodically deflected along the scanning direction at a stationary bar code, or in which a bar code is moved along the scanning direction through a stationary transmitted light beam.
The transmitted light beam, which illuminates the bar code, appears as a light bead on the latter and must have a sufficiently small extent for the correct identification of the bars of the bar code. In many applications, the largest possible depth of focus is required for the bar code reading apparatus, i.e. the light bead should retain a sufficiently small extent along the largest possible reading range in front of and behind the bar code. For this purpose, in addition to the use of image forming optical systems, the use of diaphragms with diaphragm apertures is known, which restrict the cross-section of the transmitted light beam and permit the boundary of the aperture to be subdivided in the initially named manner with respect to the scanning direction into two oppositely disposed transverse sections and two oppositely disposed longitudinal sections.
The limitation of the extent of the light bead by such diaphragms with correspondingly small openings is, however, restricted as a result of diffraction effects; the diffraction of the transmitted light beam at the boundary of the diaphragm opening means that the intensity distribution of the light bead can differ considerably from the original uniform distribution. These diffraction effects at the bar code, however, disturb the correct identification of the bars or their width in a disadvantageous manner. As a result of these effects the diaphragm aperture and thus the cross-section of the transmitted light beam can therefore not be reduced as desired, and the depth of focus of the known bar code reading apparatuses is restricted to an undesired degree.
It is an object of the invention to provide a bar code reading apparatus of the initially named kind, which has an improved depth of focus.
This object is achieved, on the one hand, in that for the compensation of diffraction effects of the transmitted light beam the boundary of the diaphragm opening has at least one compensatory projection at at least one transverse section which projects into the diaphragm aperture as an intermediate extremity with respect to this transverse section in the direction towards the oppositely disposed transverse section.
Since the compensatory projection of the invention points in the direction towards the respective oppositely disposed transverse section of the diaphragm opening, it extends at least approximately parallel to the scanning direction.
The design of the compensatory projection as an intermediate extremity is defined in that the boundary of the diaphragm aperture at the relevant transverse section is set back on both sides of the compensatory projection relative to the latter. Mathematically considered the compensatory projection with its extent along the scanning direction thus forms a maximum with respect to the relevant transverse section. The maximum can in this sense represent a local or an absolute maximum with respect to the two ends of the relevant transverse section or with respect to possible further compensatory projections.
The boundary of the relevant diaphragm aperture can, for example, have a substantially rectangular basic shape, with either the two shorter or the two longer sides of the rectangle extending transversely to the scanning direction and thus, in accordance with the definition, forming the transverse section provided with a compensatory projection. In similar manner the boundary of the diaphragm aperture can also have an oval or round basic shape.
The compensatory projection of the invention brings about in desired manner an at least partial smudging or superimposition of those diffraction effects which are caused by the stopping down of the transmitted light beam at the boundary of the diaphragm aperture and which produce fluctuations of the intensity distribution of the resulting light bead at a bar code. A desired compensation arises in that the compensatory projection itself causes diffraction effects, which at least partly counteract the undesired diffraction effects and smudge or mutually smear the latter.
The compensatory projection thus causes an approximately continuous and uniform transition of the intensity from the center of the transmitted light beam to its edge region. In doing so, it is not essential that all diffraction effects are cancelled, but rather than the negative effects are at least substantially reduced, so that in advantageous manner a more pronounced bounding and bundling of the transmitted light beam can be achieved. In this way a greater depth of focus is achieved with the bar code reading apparatus of the invention.
The diaphragm of the invention proves to be particularly advantageous if the cross-section in accordance with the invention is intended to blank out a part of the transmitted light beam which has a relatively high or indeed similar intensity in comparison to the center of the cross-section of the transmitted light beam, which ultimately leads to pronounced diffraction effects.
This case can, for example, occur if a transmitted light beam with elliptic cross-section is to be restricted by means of a diaphragm aperture of basic rectangular shape in such a way that the transverse sections of the boundary of the diaphragm aperture blank out a significantly greater part of the elliptic cross-section of the transmitted light beam than the longitudinal sections.
The fact that the compensatory projection is provided at at least one transverse section of the diaphragm aperture, i.e. at a section which stands transversely to and thus substantially perpendicular to the scanning direction, yields the following special advantage: Through such a compensatory projection the diffraction maxima and minima of the light bead at the bar code, which are caused by the boundary of the diaphragm aperture, can in particular be reduced. These diffraction maxima and minima otherwise appear as an intensity pattern extending substantially parallel to the direction in which the bar code bars extend and thus particularly greatly impair a correct identification of the bar code. Such diffraction maxima and diffraction minima are broken through by the diffraction effects caused by the compensatory projection.
A further advantage of the diaphragm of the invention lies in the fact that it can be manufactured in simple manner. The openings of customary diaphragms are, for example, produced by laser cutting, etching, punching or drilling. In this connection the provision of one or more compensatory projections in the boundary of the diaphragm aperture represents no significant extra cost or effort or only a slight additional cost and effort.
In preferred embodiments of the compensatory projection of the invention, the latter is formed as a tooth or as a tongue, in which, for example, two straight or curved boundaries form the outline of the compensatory projection. These two boundaries can include an acute or an obtuse angle with one another. The compensatory projection can also be formed as a uniformly roundly shaped tongue, or as a rectangular tongue. Furthermore, it is possible to endow the outline of the compensatory projection with a stochastic pattern which intentionally produces chaotic diffraction patterns for the desired purpose of compensation of diffraction effects.
Finally, it is also possible to provide the compensatory projection additionally with lateral cutouts or projections in order to further enhance the desired effect of the mutual compensation of the diffraction effects that are produced.
The boundary of the diaphragm aperture can have a compensatory projection at its two transverse sections, so that the desired compensation of diffraction effects takes place both in the selected direction of scanning as well as opposite thereto. Furthermore it is preferred if the relevant transverse section or the two transverse sections have a plurality of compensatory projections. Moreover, one or more compensatory projections of the named kind can also be formed at a longitudinal section or at both longitudinal sections of the boundary of the diaphragm aperture.
Through a plurality of compensatory projections the compensation of diffraction effects can be particularly effectively produced by their mutual mixing and blurring. These several compensatory projections preferably form a stochastic arrangement, i.e. a non-periodic and in particular intentionally chaotic arrangement along the relevant transverse section. In this way the occurrence of periodic diffraction or interference patterns can be avoided. A periodic arrangement of a plurality of compensatory projections can also bring about the desired compensation of the diffraction effects.
The object of the invention is solved for a bar code reading apparatus of the initially named kind, amongst other things, also in that a filter is arranged at at least one transverse section or longitudinal section of the boundary of the diaphragm aperture for the compensation of diffraction effects of the transmitted light beam and brings about a continuous or a step-wise transition for the transmission of the transmitted light beam through the diaphragm aperture from substantially 100% at the center of the diaphragm aperture to 0% outside of the boundary of the diaphragm aperture.
Thus, this possibility of solution also aims at compensating for the diffraction effects which occur at the boundary of the diaphragm aperture by damping the light intensity.
The distribution of the degree of transmission of the filter can, for example, be a continuous distribution, in particular a linear or a Gaussian curve distribution. The degree of transmission can, however, also have a discontinuous, in particular a step-likes, distribution, for example in order to intentionally damp individual diffraction maxima, which would otherwise express themselves as an intensity maximum in a light bead at a bar code. Alternatively, the filter can also be formed as least regionally as a gray filter, so that it has a substantially constant degree of transmission in these regions. A filter of the explained kind is preferably provided at the two transverse sections of the boundary of the diaphragm aperture. It is, however, also possible for each section of the boundary to have such a filter. The filter can in particular be formed as a round filter, which is arranged along the entire boundary of the diaphragm aperture.
The invention, moreover, extends to a diaphragm with a diaphragm aperture, by which the cross-section of a light beam is to be restricted, and the boundary of which has two longitudinal sections and two transverse sections, insofar as this diaphragm has features of a diaphragm such as is described in connection with the bar code reading apparatus of the invention. A diaphragm of this kind can also be used in diverse manner in apparatuses other than the bar code reading apparatus of the invention.


A lithographic printing plate support capable of obtaining a presensitized plate which is excellent in scumming resistance and scratch resistance and achieves a good balance between sensitivity and press life, and a method of manufacturing the support are provided. The support includes a surface which has an arithmetic mean roughness Ra of 0.36 to 0.50 μm; not more than 3.0 recesses with a depth of at least 4 μm per 400 μm square region; and a surface area ratio ΔS5(0.02-0.2) determined from Sx5(0.02-0.2) denoting the actual surface area of a 5 μm square surface region as determined by three-point approximation based on data obtained by extracting 0.02 to 0.2 μm wavelength components from three-dimensional data on the surface region measured with an atomic force microscope at 512×512 points and S0 denoting the geometrically measured surface area of the surface region, of 50 to 90%.

The present invention relates to a lithographic printing plate support and a method of manufacturing the same. More specifically, the invention relates to a lithographic printing plate support capable of obtaining a presensitized plate for lithographic printing which is excellent in scratch resistance and achieves a good balance between sensitivity and press life, and a method of manufacturing the same.
Lithographic printing is a process that makes use of the inherent immiscibility of water and oil. Lithographic printing plates used in lithographic printing have formed on a surface thereof regions which are receptive to water and repel oil-based inks (referred to below as "non-image areas") and regions which repel water and are receptive to oil-based inks (referred to below as "image areas").
The surface of the aluminum support employed in a lithographic printing plate (referred to below simply as a "lithographic printing plate support") is used to carry non-image areas, and must therefore have a number of conflicting properties, including, on the one hand, excellent hydrophilicity and water retentivity and, on the other hand, excellent adhesion to the image recording layer that is formed thereon. If the surface of the lithographic printing plate support is not hydrophilic enough, ink will adhere to non-image areas during printing, causing ink buildup on the blanket cylinder and, in turn, scumming. That is, the scumming resistance of the plate will worsen.
Scratch-like dropouts occur on an image due to striking of a presensitized plate against something when it is handled, slight rubbing of the presensitized plate against interleaving paper, or slight touching as touching a plate surface by a finger, and hence its handling during the plate making operation is now difficult. In order to enhance the scratch resistance, attempts have been made to lower the coefficient of friction by forming a layer made of a fluorochemical surfactant or a waxing compound on the surface of a recording layer. However, a satisfactory solution has not been obtained yet.
The smoother the surface of the lithographic printing plate support is, the smoother the recording layer formed thereon is, hence the more excellent the resulting lithographic printing plate is in scratch resistance. However, if the surface of the lithographic printing plate support is too smooth, adhesion of the lithographic printing plate support to the recording layer is impaired, which readily causes the recording layer to come off, thus leading to deterioration of the durability (press life) when a large number of impressions are made.
When locally deep recesses are formed on the surface of a lithographic printing plate support, a lithographic printing plate having a positive-type image recording layer formed on the support has a problem that locally deep portions in non-image areas are not readily developed, whereas a lithographic printing plate having a negative-type image recording layer formed on the support has a problem that image is not readily formed in locally deep portions of image areas, leading to lowering of the sensitivity.
In order to enhance various performance characteristics such as scumming resistance, scratch resistance, sensitivity and press life, asperities are formed on the surface of the lithographic printing plate support through various surface graining treatments.
JP 2003-112484 A (the term "JP XXXX-XXXXXX A" as used herein means an "unexamined published Japanese patent application") describes a lithographic printing plate support which is obtained by subjecting an aluminum plate to graining treatment and anodizing treatment and which has on the surface thereof a grained shape of a structure in which a small wave structure having an average aperture diameter of 0.01 to 0.2 μm is superposed on a medium wave structure having an average aperture diameter of 0.5 to 5 μm. JP 2003-112484 A also describes that the lithographic printing plate obtained is excellent in press life and scumming resistance.
JP 2003-1963 A describes a method of obtaining a presensitized plate for use in laser plate making which is excellent in press life and does not cause scumming on the blanket cylinder or printing paper, the method using a lithographic printing plate support obtained by subjecting an aluminum plate to mechanical graining treatment in which the aluminum plate is scrubbed with rotating brushes while abrasive particles having a mean particle size of 5 to 70 μm and containing at least 60% by mass of SiO2 are supplied thereto; etching treatment; and electrolytic graining treatment in which the aluminum plate is electrolyzed in an acidic electrolyte solution.
JP 2004-148798 A describes a lithographic printing plate support which has a surface area ratio ΔS50 defined by formula (11):ΔS50(%)=[(Sx50−S0)/S0]×100(%)  (11)wherein Sx50 is the actual surface area of a 50 μm square surface region as determined by three-point approximation from three-dimensional data on the surface region measured with an atomic force microscope at 512×512 points and S0 is the geometrically measured surface area of the same surface region, of 50 to 90%, and which has a steepness a 4550(0.02-0.2), defined as the surface area percentage represented by areas where the slope is 45° or more in the data obtained by extracting the 0.02 to 0.2 μm wavelength components from the above three-dimensional data, of 5 to 40%.

Lithographic printing plate support and method of manufacturing the same


A pneumatic amplifier includes a valve body, a first comparison chamber, a third comparison chamber and a second comparison chamber. A first diaphragm and a second diaphragm are arranged in the first comparison chamber and fixed to the valve body. A mounting plate A is fixedly arranged between the first diaphragm and the second diaphragm. A seventh diaphragm, an eighth diaphragm, a ninth diaphragm and a tenth diaphragm are arranged in the second comparison chamber and fixedly arranged on the valve body. A mounting plate C is fixedly arranged among the seventh diaphragm, the eighth diaphragm, the ninth diaphragm and the tenth diaphragm. A third diaphragm, a fourth diaphragm, a fifth diaphragm and a sixth diaphragm are arranged in the third comparison chamber and fixed to the valve body. A mounting plate B is fixedly arranged among the third diaphragm, the fourth diaphragm, the fifth diaphragm and the sixth diaphragm.

FIG. 6 is a schematic structural diagram of a conventional double-acting amplifier. When the control pressure Pn is changed, a diaphragm 107 is forced to change to drive a valve stem 111 to move, and the valve stem 111 drives a valve core 101/109 to move to change the output pressure of Pout1 and Pout2.
When Pn increases, the diaphragm 106/107, under the combined action of Pn and Psup, drives the valve stem 111 to move to the left, and the valve core 109 to move to the left, an intake valve port of Pout1 is opened, a deflation valve port of Pout1 is closed, and the Pout1 pressure is increased. Meanwhile, the valve core 101 also moves to the left, an intake valve port of Pout2 is closed, a deflation valve port of Pout2 is opened, and the Pout2 pressure is lowered.
When Pn decreases, the diaphragm 106/107, under the combined actin of Pn and Psup, drives the valve stem 111 to move to the right, and the valve core 109 to move to the right, the intake valve port of Pout1 is closed, the deflation valve port of Pout1 is opened, and the Pout1 pressure is lowered. Meanwhile, the valve core 101 also moves to the right, an intake valve port of Pout2 is opened, the deflation valve port of Pout2 is closed, and the Pout2 pressure is increased.
Assuming that the effective area of the diaphragm 106 is S1, the effective area of the diaphragm 107 is S2, the effective area of Pout1 acting on the valve stem 111 is S3, and the effective area of Pout2 acting on the valve stem 111 is S4, under ideal cases, a force balance equation of the valve stem is:Pn*S1+Psup*S2+Pout2*S4=Pout1*S3+Psup*S1  Formula 1
In general cases, S3=S4, S1>S2, the above equation may be simplified as:Pout1−Pout2=[Pn*S1−Psup*(S1−S2)]/S3  Formula 2
Equation 2 shows that the conventional double-acting amplifier can only control an output pressure difference, rather than the output pressure. To solve this problem, adjusting screws 104 are additionally arranged to adjust the output pressure when the output pressure difference is zero. Therefore, the two outputs of the double-acting amplifier interfere with each other and require manual adjustment.
When the amplifier is used in a single-acting mode, it is necessary to move a valve core mounting base 102 by means of the adjusting screws 104 to drive the valve core 102 out of contact with the valve stem 111. Therefore, when the conventional pneumatic amplifier is used in different modes of single and double actions, the adjustment points of the amplifier are different and require manual re-adjustment.
The above problems make it impossible for the pneumatic amplifier to switch between single-acting and double-acting operating modes at the working site. Adjustments can only be made at a factory.
Since the sealing of the valve stem 111 relies on an O-ring 103/108, the friction force is large during normal operation, resulting in a long response time of the pneumatic amplifier and a serious hysteresis.

MERCURY INSTRUMENTS (CHENGDU) CORPORATION


A fixing roller includes: a core; an elastic layer made of an elastic material, formed around the core; and a resin layer made of fluorine resin, formed around the elastic layer. The fixing roller is designed such that the resin layer has a thickness of 40 μm or more, and the fixing roller meets a relation Tr≧Tc+60 or Tr≧Tc+75 where Tr (° C.) is a limit temperature obtained in a predetermined peeling test and Tc (° C.) is a temperature of the fixing roller at which a fixing process is performed. This allows the fixing roller used in an image forming apparatus with a high process speed to secure that the resin layer is less likely to be detached from the elastic layer.

In general, a fixing roller used in an electrophotographic image forming apparatus (e.g. a copying machine, a multifunctional apparatus, and a printer), particularly a fixing roller used in a color printer, includes a structure in which an elastic layer made of silicone rubber is formed around a metal core and a resin layer (surface layer) made of a PFA tube is provided around the elastic layer.
The fixing roller coated with the PFA tube is produced in such a manner that a PFA tube whose internal surface has been subjected to an etching treatment and to application of primer is fixed to the inside of a cylindrical mold, a core is inserted into the PFA tube, and then silicone rubber is poured into a space between the core and the PFA tube, and the silicone rubber is heated and cured, so that the PFA tube and the silicone rubber are molded integrally.
Further, in the fixing roller, a PFA tube with a thickness of 30 μm is generally used in order that elasticity of silicone rubber is impaired as little as possible, a wider nip width and a higher detachability of a sheet are secured, and unevenness in luster does not appear.
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2001-312169 (Tokukai 2001-312169; published on Nov. 9, 2001)
However, the above fixing roller has inconvenience. When the fixing roller is used in a high-speed printer whose process speed (peripheral velocity of the fixing roller) is 300 mm/s or more, mechanical and thermal stress applied on the PFA tube is large, resulting in occurrence of wrinkles on the PFA tube.
An effective way to prevent such wrinkles is to make the PFA tube thicker (e.g. 40 μm or more), thereby increasing mechanical strength of the PFA tube. However, as a result of a test, the inventors of the present invention found that as the PFA tube becomes thicker, the PFA tube (resin layer) is more likely to be detached from the silicone rubber (elastic layer) at their interface. The reason is as follows: making the PFA tube thicker reduces flexibility of the PFA tube, and accordingly the PFA tube cannot sufficiently follow deformation of the silicone rubber, resulting in occurrence of shearing stress between the PFA tube and the silicone rubber.
In particular, in a case where the thickness of the silicone rubber (the thickness of the elastic layer) is large and/or hardness of the silicone rubber is low, deformation (shearing stress) of the elastic layer made of the silicone rubber gets large, which exhibits the above problem.
In order to solve the above problem, paragraph [0020] of Patent Document 1 discloses a method for adhereing a PFA tube, including steps (1) to (4) as follows: (1) a rubber roller made of silicone rubber is coated with a PFA tube, (2) an adhesive made of silicone rubber with self-adhesiveness is poured between the rubber roller and the PFA tube, (3) the PFA tube is squeezed by an O-ring so that the poured adhesive spreads from one end of the PFA tube to the other end of the PFA tube, and (4) the adhesive is heated and cured so that the PFA tube is adhered to the rubber roller. However, this method requires a far more complex manufacture process compared with a conventional manufacture method and has a difficulty in evenly forming an adhesive layer with a predetermined thickness, resulting in problems in quality and cost up.
For that reason, there is a request for a fixing roller that is different from the fixing roller disclosed in Patent Document 1 and that can prevent the above problem (the problem such that the elastic layer made of silicone rubber is likely to be detached from the resin layer made of the PFA tube).

Fixing roller and image forming apparatus


A hybrid power train for a vehicle may include an input shaft, an engine side driving gear mounted at the input shaft, an output shaft, an engine side driven gear fixedly mounted at the output shaft and meshed with the engine side driving gear, a motor side driving gear and mounted to rotate by the motor, a motor side driven gear fixedly mounted at the output shaft and meshed with the motor side driving gear, an output gear rotatably mounted at the output shaft, a one way clutch mounted between the output gear and the output shaft, a clutch device mounted on the output shaft, and a planetary gear apparatus engaging between the output shaft and the output gear.

1. Field of the Invention
The present invention relates to a hybrid power train for a vehicle, and more particularly, to a technology of a power train for a vehicle capable of providing a driving force of a vehicle as power output from an engine which is an internal combustion engine and a motor driven with electricity.
2. Description of Related Art
A hybrid power train to drive a vehicle by properly and harmoniously operating power generated from an engine which is an internal combustion engine and power generated from a motor driven with electricity basically uses a complementary aspect of a torque characteristic of the engine and a torque characteristic of the motor to improve driving efficiency of a vehicle.
Therefore, the hybrid power train according to the related art implements an EV mode which uses the characteristic of the motor with an excellent low speed torque characteristic by allowing the motor to drive the vehicle mainly at the time of a starting of the vehicle or in a low speed condition, implements an engine mode which allows the engine with a relatively excellent torque characteristic to drive the vehicle in a middle speed or high speed condition, and implements a hybrid mode which may use the torques of the engine and the motor in a driving condition demanding a high torque.
The hybrid power train used in the vehicle may implement a plurality of shift stages for each mode by a simple configuration if possible, while implementing various driving modes by maximally using the torque characteristics of the engine and the motor as described above.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

This patent is subject to a terminal disclaimer.


A formed article for making alloying additions to metal melts includes particles of at least one master alloy and a binder material binding the particles of the master alloy in the formed article. The binder material changes form and frees the master alloy particles when the formed article is heated to a predetermined temperature, preferably a temperature greater than 500° F. A method for making an alloy also is provided. The method includes preparing a melt comprising a predetermined quantity of a master alloy wherein the master alloy is added to the melt or the melt starting materials in the form of particles of the master alloy bound into at least one formed article by a binder material that decomposes at a predetermined temperature, preferably a temperature greater than 500° F., and releases the particles of master alloy.

1. Field of Technology
The present disclosure relates to articles including master alloy, and to certain methods of making and using those articles. More particularly, the present disclosure relates to formed articles including master alloy used for making alloying additions to a metal melt, and to certain methods of making and using such formed articles.
2. Description of the Background of the Technology
During production of stainless steel, titanium alloys, and other alloys, quantities of raw feed materials, often including scrap, are heated at high temperature to produce a melt having the desired elemental chemistry. It is often the case that quantities of one or more master alloys are added to the raw feed materials or to the melt to suitably adjust the elemental chemistry of the melt prior to solidifying the melt into an ingot, a billet, a powder, or some other form. As is known in the art, a master alloy is an alloy rich in one or more desired addition elements and is included in a metal melt to raise the percentage of the desired constituent in the melt. ASM Metals Handbook, Desk Edition (ASM Intern. 1998), p. 38.
Because the elemental composition of the master alloy is known, it theoretically is simple to determine what amount of a master alloy must be added to achieve the desired elemental chemistry in the melt. However, one must also consider whether all of the added quantity of the master alloy will be fully and homogenously incorporated into the melt. For example, if the actual amount of the master alloy addition that melts and becomes homogenously incorporated into the melt is less than the amount added, the elemental chemistry of the melt may not match the desired chemistry. Thus, an effort has been made to develop forms of master alloys that will easily melt and readily become homogenously incorporated into a metal melt.
One example of a specific area presenting some challenge is the introduction of certain alloying additives into a titanium melt. For example, it is difficult to alloy titanium with oxygen. Titanium sponge or cobble typically is used as the titanium-rich raw feed material when preparing titanium alloy melts. A conventional method of increasing the oxygen content of a titanium alloy melt involves compacting titanium sponge with powdered titanium dioxide (TiO2) master alloy. As the titanium dioxide master alloy dissolves and becomes incorporated into the melt, it increases the oxygen content of the molten material, and subsequently also increases the oxygen content of the solid material formed from the melt. The process of compacting the sponge and titanium dioxide powder has several drawbacks. For example, it is costly to weigh out and compact the materials. Also, preparing the compacted sponge and titanium dioxide powder requires a significant amount of time prior to the melting and solidifying/casting process.
A known alternative method for adding oxygen to a titanium melt is simply to mix a quantity of a loose powdered titanium dioxide master alloy with the titanium sponge and/or cobble raw feed materials in the melting vessel prior to heating the materials. In this method, relatively small amounts of the powdered titanium dioxide coat the surfaces of the sponge and/or cobble. If more of the powdered titanium dioxide is added, it will fail to stick to the starting materials and will segregate from those materials. This "free" titanium dioxide powder is prone to be carried away by air movement. Also, large portions of loose titanium dioxide powder that collect in the melting vessel may not be homogenously incorporated into the melt. Accordingly, a possible result of using this conventional titanium dioxide addition technique to adjust the chemistry of a titanium alloy melt is an inconsistent and unpredictable loss of titanium dioxide. The final result can be a titanium alloy product that does not have the expected elemental chemistry.
Given the above, titanium alloy producers typically use the alloying technique of adding loose powdered titanium dioxide when producing titanium alloys having small oxygen additions. Nevertheless, even in such cases the final level of oxygen achieved is somewhat unpredictable. When higher oxygen levels are desired than can be readily achieved by the addition of loose titanium dioxide powder, the titanium sponge/titanium dioxide powder compaction technique is often used, with the aforementioned lead time and cost disadvantages.
Given the drawbacks of conventional techniques of adding alloying oxygen to titanium melts, it would be advantageous to provide an improved alloying technique. More generally, it would be advantageous to provide an improved general technique for making various alloying additions to a wide variety of metal melts.

Formed articles including master alloy, and methods of making and using the same


An improved device and method are provided for bundling debris, such as tree, shrubbery and rosebush trimmings and the like. The device has an elongate body member with a grip, a guide with an opening, and a retainer. An elongate flexible member, which has a connector at one end detachably connected to the retainer and a handle at the other end, is adapted to be slidably displaced through the opening to compress the debris from an uncompacted configuration to a compacted configuration. An adapter is provided to releasably maintain the debris, in conjunction with the flexible member, in the compacted configuration as a binder is tied around the debris to form a transportable bundle of the debris in the compacted configuration. The device may optionally be integrally constructed, including a binder holder with or without a top for foot bearing purposes and/or a cutter for the binder, if desired. The device also includes a hook, or the like, to engage the binder about the bundle for manually transporting the bundle for disposal thereof. A method of using the device is described for bundling the debris.

1. Field of the Invention.
The present invention relates generally to disposing of waste materials, and, in particular, to disposing of tree, shrubbery and rosebush trimmings and the like.
2. Description of the Related Art.
Landfills have been used to dispose of a multitude of different types of waste. Such waste has originated from many different sources. Due to the expansiveness of the population and the general wastefulness of our society, the quantity of that waste has placed tremendous burdens on the available landfills, and the methods of picking up that waste and delivering it to those landfills has pushed present capabilities to process that waste almost to beyond capacity.
In response to these burdensome demands required by our society, many cities now require yard waste such as grass cuttings and tree, shrubbery and rosebush trimmings to be bundled separately from other garbage. For example, many cities have mandated that such trimmings must be properly bundled or the waste collectors will not remove the trimmings from the property but will be left curbside until they are property bundled. In addition, many of those municipalities not only specify that the trimmings be bundled, but that the bundles not exceed a certain length, a certain weight, or both. The mandated sizes of the bundles generally range between 3'-6', with most cities specifying a maximum length of 4'. The mandated weights of the bundles generally range between 25-80 pounds, with many of the cities specifying a maximum weight of 50 pounds.
One problem commonly incurred during the handling and disposing of branches and trimmings is the uncooperative nature thereof. As one tries to bundle such items, the stiffness and bulkiness resists reasonable efforts to manually compress the limbs into a compact bundle which is easier to handle because it is not so bulky. Various rudimentary techniques have been attempted, largely without success, but accepted out of frustration. Many times that frustration was further aggravated due to slippage of the cord binding the bundle, thereby losing whatever advantage had been initially gained.
As a result, the limbs generally were not compressed into conveniently sized bundles and more trips were required to carry the bundles to curbside for further disposition. In addition, the bundles sometimes contain trimmings from rosebushes, locust trees, and other thorny flora which is capable of inflicting injury, sometimes severe, not only to the flesh of those carrying the bundles but also to ones clothes.
What is needed is a device and a method whereby trimmings from trees, shrubbery, rosebushes, and the like can be quickly, easily, conveniently and reliably compressed into compact bundles and manually carried to curbside or other desired location with minimal effort and risk to flesh or clothing.

Device with flexible elongate member for binding and toting tree trimmings and the like


Modular transfer band assemblies and systems are provided. The modular transfer band assemblies may include a frame, pulleys supported by the frame, and a belt provided around the pulleys. The belt is configured to be driven to transfer an article off of a main conveyor line having rollers for conveying the article. The removable belt module is configured to be engaged and disengaged from the main conveyor line without the use of tools as a single, self-contained unit. Modular transfer band assembly systems may include the modular transfer band assembly and a support structure, wherein the modular transfer band assembly is removably attached to the support structure.

Conveyor systems transport items down a primary conveying line. Often, the conveyor system will include transfer section which is used to divert, transfer, or otherwise move the items off the primary conveying line and onto branch or intersecting lines.
An example of such a transfer section is a right angle transfer unit, which is a device placed at the intersection of two perpendicular conveyor lines, to transfer an item from the main line to the intersecting conveyor line. The unit may include rollers conveying in the primary direction, and belts interspersed between the rollers which move in a direction perpendicular to the primary direction. The belts move when items are needed to be moved off of the main conveyor and onto the perpendicular conveyor.
Belts and components can wear out in such systems and require replacement. Replacement of belts and components in such systems can be difficult, time-consuming, and expensive. Moreover, such systems can require many interrelated components, all of which add to the cost of the system. Additionally, assembly and/or repair of such systems can be time-consuming and expensive, requiring use of multiple tools and the fitting of multiple components within tight spaces. In particular, repair of such systems can require multiple other components be removed to access the worn or broken component and replacement of that component, thus resulting in total system downtime. Additionally, the belts in such systems can often come off track, requiring replacement or repair.
Accordingly, it is desired to provide improvements in conveyor transfer systems and/or embodiments which address one or more of the foregoing problems.

Modular conveyer transfer systems and methods


To provide a semiconductor device of high reliability by arranging TFTs that have appropriate structures in accordance with circuit functions. In a semiconductor device having a driver circuit portion and a pixel portion on the same insulator, gate insulating films of a driver TFT are designed to be thinner than a gate insulating film of a pixel TFT. In the pixel TFT, channel forming regions are formed under a gate electrode, and a separation region is formed between the channel forming regions. At this point, LDD regions have a region that overlaps with the gate electrode and a region that does not.

1. Field of the Invention
The present invention relates to a semiconductor device having a circuit that comprises a thin film transistor (hereinafter referred to as TFT). For instance, the invention relates to the structure of an electrooptical device represented by a liquid crystal display and an EL display, and of an electronic equipment equipped with such electrooptical device as one of its parts. The term 'semiconductor device' in this specification designates devices in general which utilize semiconductor characteristics to function and, therefore, the electrooptical device, the semiconductor circuit and the electronic equipment all fall into the range of the semiconductor device.
2. Description of the Related Art
Application of TFTs (Thin Film Transistors) to active matrix liquid crystal displays (hereinafter referred to as AM-LCDs) has actively been developed because TFTs allow of the use of inexpensive substrates on which they are to be formed. Among TFTs, the one that utilizes a crystalline semiconductor film (typically, a polysilicon film) can provide a high mobility and hence is considered to be suitable for integrating functional circuits on the same substrate to realize image display of high definition.
Basically, an AM-LCD comprises a pixel portion (a region where a plurality of pixels are arranged) for displaying an image and a driver circuit portion for driving a TFT of each of the pixels arranged in the pixel portion, the portions formed on the same substrate. The driver circuit portion may be divided into a gate line driver circuit (gate driver circuit) driving a gate line and a source line driver circuit (source driver circuit) transmitting a video signal to each TFT.
In the System on Panel, proposed lately, a logical circuit portion including a signal divider circuit, γ correction circuit is formed on the same substrate other than the pixel portion and the driver circuit (also called as a peripheral driver circuit) portion.
However, capabilities required for TFTs are different between the pixel portion and the driver circuit portion, thereby making it difficult to meet all ways with one TFT structure. In other words, the TFT structure in which a TFT for forming a driver circuit such as a shift resister circuit or a latch circuit where the importance is attached to high speed operation is compatible with a TFT for forming a buffer circuit, a sampling circuit, or a pixel circuit that gives importance to high withstand voltage characteristic has not been established yet under the present circumstances.

Electrooptical device and a method of manufacturing the same

Semiconductor Energy Laboratory Co., Ltd.