A method for retransmitting coded bits by a transmitter in response to a retransmission request from a receiver in a mobile communication system. The method comprises determining a modulation technique to be used at retransmission as a modulation technique having a lower modulation order than a modulation technique used at initial transmission; determining a puncturing pattern according to an HARQ (Hybrid Automatic Repeat Request) type, and selecting as many coded bits as the number of coded bits that can be symbol-mapped by the determined modulation technique, among the coded bits punctured by the determined puncturing pattern; and symbol-mapping the selected coded bits by the determined modulation technique, and transmitting the symbol-mapped coded bits to the receiver.

1. Field of the Invention
The present invention relates generally to a data transceiver apparatus and method in a CDMA (Code Division Multiple Access) mobile communication system, and in particular, to an apparatus and method for transmitting and receiving data using a variable modulation technique during retransmission.
2. Description of the Related Art
Presently, the mobile communication system has evolved from an early voice-based communication system to a high-speed, high-quality radio data packet communication system for providing a data service and a multimedia service. In addition, a 3rd generation mobile communication system, divided into an asynchronous 3GPP (3rd Generation Partnership Project) system and a synchronous 3GPP2 (3rd Generation Partnership Project 2) system, is being standardized for a high-speed, high-quality radio data packet service. For example, standardization on HSDPA (High Speed Downlink Packet Access) is performed by the 3GPP, while standardization on 1xEV-DV (1xEvolution-Data and Voice) is performed by the 3GPP2. Such standardizations are implemented to determine solutions for high-speed, high-quality radio data packet transmission services of 2 Mbps or more in the 3rd generation mobile communication system. Further, a 4th generation mobile communication system has been proposed, which will provide a high-speed, high-quality multimedia service superior to that of the 3rd generation mobile communication system.
A principal factor that impedes a high-speed, high-quality radio data service lies in the radio channel environment. The radio channel environment frequently changes due to a variation in signal power caused by white noise and fading, shadowing, Doppler effect caused by the movement of and the frequent change in speed of a UE (User Equipment), and interference caused by other users and multipath signals. Therefore, in order to provide a high-speed radio data packet service, there is a need for an improved technology capable of increasing adaptability to variations in the channel environment in addition to the general technology provided for the existing 2nd or 3rd generation mobile communication system. A high-speed power control method used in the existing system also increases adaptability to variations in the channel environment. However, both the 3GPP and the 3GPP2, implementing standardization on the high-speed data packet transmission, reference the AMCS (Adaptive Modulation/Coding Scheme) and HARQ (Hybrid Automatic Repeat Request) techniques.
The AMCS is a technique for adaptively changing a modulation technique and a coding rate of a channel encoder according to a variation in the downlink channel environment. Commonly, to detect the downlink channel environment, a UE measures a signal-to-noise ratio (SNR) and transmits the SNR information to a Node B over an uplink. The Node B predicts the downlink channel environment based on the received SNR information, and designates a proper modulation technique and coding rate according to the predicted value. The modulation techniques available for the AMCS include QPSK (Quadrature Phase Shift Keying), 8PSK (8-ary Phase Shift Keying), 16QAM (16-ary Quadrature Amplitude Modulation), and 64QAM (64-ary Quadrature Amplitude Modulation), and the coding rates available for the AMCS include ½ and ¾. An AMCS system applies the high-order modulations (16QAM and 64QAM) and the high coding rate ¾ to the UE located in the vicinity of the Node B, having a good channel environment, and applies the low-order modulations (QPSK and 8PSK) and the low coding rate ½ to the UE located in a cell boundary. In addition, compared to the existing high-speed power control method, the AMCS decreases an interference signal, thereby improving the average system performance.
The HARQ is a link control technique for correcting an error by retransmitting the errored data upon an occurrence of a packet error at an initial transmission. Generally, the HARQ is classified into Chase Combining (CC), Full Incremental Redundancy (FIR), and Partial Incremental Redundancy (PIR).
CC is a technique for transmitting a packet such that the whole packet transmitted at a retransmission is equal to the packet transmitted at the initial transmission. In this technique, a receiver combines the retransmitted packet with the initially transmitted packet that is previously stored in a buffer. By doing so, it is possible to increase reliability of coded bits input to a decoder, thus resulting in an increase in the overall system performance. Combining the two same packets is similar to repeated coding in terms of the effects, so it is possible to increase a performance gain by about 3 dB on average.
FIR is a technique for transmitting a packet comprised of only redundant bits generated from the channel encoder instead of the same packet, thus improving performance of a decoder in the receiver. That is, the FIR uses the new redundant bits as well as the initially transmitted information during decoding, resulting in a decrease in the coding rate, which in turn thereby improves performance of the decoder. It is well known in coding theory that a performance gain by a low coding rate is higher than a performance gain by repeated coding. Therefore, the FIR is superior to the CC in terms of only the performance gain.
Unlike the FIR, the PIR is a technique for transmitting a combined data packet of the information bits and the new redundant bits at retransmission. Therefore, the PIR can obtain the similar effect as the CC by combining the retransmitted information bits with the initially transmitted information bits during decoding, and also obtain the similar effect as the FIR by performing the decoding using the redundant bits. The PIR has a coding rate slightly higher than that of the FIR, showing intermediate performance between the FIR and the CC. However, the HARQ should be considered in the light of not only the performance but also the system complexity, such as a buffer size and signaling of the receiver. As a result, it is difficult to determine which technique is optimal for a given system.
The AMCS and the HARQ are separate techniques for increasing adaptability to the variations in the link environment. It is possible to remarkably improve the system performance by combining the two techniques. That is, the transmitter determines by the AMCS, a modulation technique and a coding rate proper for a downlink channel condition and then transmits packet data according to the determined modulation technique and coding rate. Then, upon failure to decode the data packet transmitted by the transmitter, the receiver sends a retransmission request. Upon receipt of the retransmission request from the receiver, the Node B retransmits the data packet by the HARQ.
FIG. 1 illustrates an existing transmitter for high-speed packet data transmission, wherein it is possible to realize various AMCS techniques and HARQ techniques by controlling a channel encoder 112.
Referring to FIG. 1, the channel encoder 112 is comprised of an encoder (not shown) and a puncturer (not shown). When input data at a determined data rate is applied to an input terminal of the channel encoder 112, the encoder performs encoding in order to decrease a transmission error rate. Further, the puncturer punctures an output of the encoder according to a coding rate and an HARQ type previously determined by a controller 122, and provides its output to a channel interleaver 114. The future mobile communication system needs a powerful channel coding technique in order to reliably transmit high-speed multimedia data. The channel encoder 112, as illustrated in FIG. 2, is comprised of a turbo encoder 200 with a mother coding rate of R=⅕, a puncturer 216 and a buffer 202. It is known in the art that channel coding by a turbo encoder performs closest to the Shannon limit in terms of a bit error rate (BER) even at a low SNR. Channel coding by a turbo encoder has also been adopted for the HSDPA and 1xEV-DV standardization by the 3GPP and the 3GPP2. The output of the turbo encoder 200 can be divided into systematic bits and parity bits. The "systematic bits" refer to actual information bits to be transmitted, while the "parity bits" refer to a signal used to help a receiver correct a possible transmission error. The puncturer 216 selectively punctures the systematic bits or the parity bits output from the encoder 200, satisfying a determined coding rate. The systematic bits and the parity bits from the turbo encoder 200 are temporarily stored in the buffer 202, to be used during retransmission at a retransmission request of the receiver.
Referring to FIG. 2, upon receiving one input data frame, the turbo encoder 200 outputs the intact input data frame as a systematic bit frame X, and further outputs two different parity bit frames Y1 and Y2. In addition, the turbo encoder 200 outputs two different parity bit frames Z1 and Z2 by performing interleaving and encoding on the input data frame. The systematic bit frame X and the parity bit frames Y1, Y2, Z1 and Z2 are provided to the puncturer 216 in a transmission unit of 1, 2, . . . , N. The puncturer 216 determines a puncturing pattern according to a control signal provided from the controller 122 of FIG. 1, and performs puncturing on the systematic bit frame X, and the four different parity bit frames Y1, Y2, Z1 and Z2 using the determined puncturing pattern, thus outputting desired systematic bits S and parity bits P. Here, the buffer 202 is provided between the turbo encoder 200 and the puncturer 216 in order to facilitate realization of the HARQ. That is, when IR (Incremental Redundancy) is used as the HARQ, different coded bits must be transmitted at each retransmission. Therefore, all coded bits generated by the turbo encoder 200 at a mother code rate are stored in the buffer 202, and the stored coded bits are output according to a corresponding puncturing pattern at each retransmission. If the buffer 202 is not provided, the same coding process must be repeated by the turbo encoder 200 at each retransmission, affecting the processing time and power efficiency. However, when CC is used as the HARQ, the same data is transmitted at each retransmission. In this case, the use of the buffer 202 causes a decrease in the efficiency, so it would be more efficient to perform a retransmission process after the channel interleaver 114 of FIG. 1.
As described above, the puncturing pattern used to puncture the coded bits by the puncturer 216 depends upon the coding rate and the HARQ type. That is, using the CC, it is possible to transmit the same packet at each transmission by puncturing the coded bits such that the puncturer 216 has a fixed combination of the systematic bits and the parity bits according to a given coding rate. Using PIR, the puncturer 216 punctures the coded bits in a combination of the systematic bits and the parity bits according to the given coding rate at initial transmission, and punctures the coded symbols in a combination of various parity bits at each retransmission, thus decreasing in the overall coding rate. For example, using the CC with the coding rate of ½, the puncturer 216 can continuously output the same bits X and Y1 for one input bit at initial transmission and retransmission, by fixedly using [1 1 0 0 0 0] in the order of the coded bits [X Y1 Y2 X′ Z1 Z2] as the puncturing pattern. Using the FIR, the puncturer 216 outputs the coded bits in the order of [X1 Y11 X2 Z21] at initial transmission and in the order of [Y21 Z21 Y12 Z12] at retransmission for two input bits, by using [1 1 0 0 0 0; 1 0 0 0 0 1] and [0 0 1 0 0 1; 0 1 0 0 1 0] as the puncturing patterns at initial transmission and retransmission, respectively. Meanwhile, though not separately illustrated, the channel encoder using R=⅓ codes adopted by the 3GPP2 can be realized by the turbo encoder 200 and the puncturer 216 of FIG. 2.
A packet data transmission operation by the AMCS system and the HARQ system realized by FIG. 1 will be described herein below. Before transmission of a new packet, the controller 122 of the transmitter determines a proper modulation technique and a coding rate based on the downlink channel condition information provided from the receiver. Thereafter, the controller 122 controls the channel encoder 112, a modulator 116 and a channel demultiplexer 118 in a physical layer based on the determined modulation technique and coding rate and a predefined HARQ type. A data rate in the physical layer is determined according to the determined modulation technique and coding rate and the number of multiple codes in use. The channel encoder 112, under the control of the controller 122, performs coding by the turbo encoder 200 and performs bit puncturing by the puncturer 216 according to a given puncturing patter, thereby outputting coded bits. The coded bits output from the channel encoder 112 are provided to the channel interleaver 114, where they are subject to interleaving. Interleaving is a technique for preventing a burst error by randomizing the input bits to disperse data symbols into several places instead of concentrating the data symbols in the same place in a fading environment. For ease of explanation, the size of the channel interleaver 114 is assumed to be greater than or equal to the total number of the coded bits. The modulator 116 symbol-maps the interleaved coded bits according to the modulation technique previously determined by the controller 122 and a given symbol mapping technique. If the modulation technique is represented by M, the number of coded bits constituting one symbol becomes log2M. Shown in Table 1 are modulation techniques used in the AMCS and the numbers of bits constituting one symbol.
TABLE 1modulation type (M)number of bits constituting one symbol (log2M)QPSK216QAM464QAM6
The channel demultiplexer 118 demultiplexes a symbol received from the modulator 116 into as many symbols as the number of multiple codes assigned by the controller 122 for high-speed data symbol transmission at a data rate determined by the controller 122. A spreader 120 spreads the demultiplexed symbols from the channel demultiplexer 118 with the assigned multiple codes. The multiple codes may include Walsh codes for identifying channels. When a fixed chip rate and a fixed spreading factor (SF) are used in the high-speed packet transmission system, the rate of symbols transmitted with one Walsh code is constant. Therefore, in order to use the determined data rate, it is necessary to use multiple Walsh codes. For example, when a system, using a chip rate of 3.84 Mcps and an SF of 16 chips/symbol, uses 16QAM and a channel coding rate of ¾, a data rate that can be provided with one Walsh code becomes 1.08 Mbps. Therefore, when 10 Walsh codes are used, it is possible to transmit data at a data rate of a maximum of 10.8 Mbps.
FIG. 3 illustrates a structure of a receiver corresponding to the transmitter of FIG. 1. Referring to FIG. 3, a despreader 312 despreads received data according to information on the multiple codes in use, the information being provided through signaling. A channel multiplexer 314 multiplexes the despread received data and provides its output to a demodulator 316. The demodulator 316 performs demodulation corresponding to the modulation used by the transmitter, and provides LLR (Log Likelihood Ratio) values for the symbols to a deinterleaver 318. The deinterleaver 318, having a structure corresponding to that of the interleaver 114 of FIG. 1, performs deinterleaving on the demodulated data and restores the original data sequence. The deinterleaved data is provided to a combiner 320, where it is combined with the same previously received data in a bit unit. If CC is used as the HARQ, the same data is transmitted at each retransmission. In this case, since combining can be performed using one buffer, a buffer controller 322 is unnecessary. However, if IR is used as the HARQ, a different redundancy packet may be transmitted at retransmission, so the buffer controller 322 is necessary. The buffer controller 322 properly assigns buffers in the combiner 320 to the received data so that the received data can be combined with the same previously received data. An output of the combiner 320 is provided to a channel decoder 324. The channel decoder 324 performs decoding on the output of the combiner 320, checks a CRC error for the received data, and transmits a NACK or ACK signal to a transmitter according to the CRC check result. Upon receiving the NACK signal from the receiver, the transmitter performs the re-transmission process according to the HARQ. However, upon receiving the ACK signal from the receiver, the transmitter begins transmission of a new data packet.
In the transmitter of the high-speed packet transmission system of FIG. 1, it is assumed that the AMCS defined by the controller 122 at initial transmission of a data packet according to a channel environment is applied even during retransmission without modification. However, as described above, a high-speed data transmission channel may subject to a change in channel environment even for an HARQ period due to the change in the number of UEs in a cell and the Doppler shift. Therefore, maintaining the modulation technique and the coding rate used at the initial transmission contributes to a reduction in the system performance. For this reason, the ongoing HSDPA and 1xEV-DV standardizations consider using the AMCS even at retransmission.
As an example, a new technique capable of changing both a modulation technique and a coding rate at retransmission has been proposed. Commonly, the size of transmittable data is changed according to a modulation technique and a coding rate, so the proposed new technique enables transmission of data by changing TTI (Time To Interleaving), a minimum unit of processing packet data. Therefore, the new technique is advantageous in that it can adjust to variations in the channel environment. However, the use of the variable TTI increases complexity of realization and signaling. Further, this technique supports only the IR among the HARQ types.
As another example, in a system wherein CC is used as the HARQ and a coding rate at retransmission is identical to a coding rate at initial transmission, if the number of available codes changes, another proposed technique changes a modulation technique for the retransmission to adapt to the change, and retransmits a part or all of the initially transmitted packet according to the changed modulation technique. Meanwhile, a receiver partially combines the retransmitted partial packet with the initially transmitted full packet, resulting in a decrease in the entire BER of a decoder. This technique, as it uses a fixed TTI and has a characteristic of partial Chase combining, is advantageous in that its realization and signaling is simple. Although this technique can decrease BER by retransmitting an unspecified part of the randomly interleaved data and combining the retransmitted partial data with the initially transmitted full packet, an improvement in a frame error rate (FER) is restrictive. In addition, this technique can support only CC among the HARQ types.
Therefore, in a communication system based on a fixed TTI, there have been demands for one method for changing a modulation technique during retransmission regardless of the HARQ type in use even though the number of available codes remains unchanged, and another method for improving system performance by properly selecting a transmission packet according to the changed modulation technique.

Transceiver apparatus and method for efficient retransmission of high-speed packet data


A laser beam machine can make quality of machining almost constant in such a manner that a first reflecting means in a first beam guide portion is moved and driven so as to maintain a length of an optical path of laser beam to be almost constant in spite of a moved position of a machining head. According to the invention, a second reflecting means for catching laser beam in a second beam guide portion is located at a position facing the first reflecting means, thereby relatively shortening a length of the optical path between the first and second reflecting means and shortening the whole length of the optical path, and maintaining quality of machining with laser beam good.

The invention relates to a laser beam machine wherein a length of an optical path of laser beam is almost constant in spite of a moved position of a machining head.
In a laser beam machine, a workpiece is machined while a machining head being moved. If a length of an optical path of laser beam changes together with a movement of a machining head, degree of collecting laser beam changes, so that it is difficult to maintain a quality of machining to be constant. Due to this reason, various kinds of laser beam machines having almost constant length of the optical path of laser beam in spite of a moved position of a machining head have been proposed (see Japanese patent applications, Publication numbers 2002-336979 and 1996(H8)-52587).
FIG. 8 is a typical view showing a structure of a conventional laser beam machine. A reference number 200 of FIG. 8 is a laser beam oscillator for generating laser beam, and a reference number 201 is a machining head for radiating laser beam on a workpiece, while being moved and driven. A reference number 202 is a machining table for locating a workpiece thereon, and reference numbers 203, 204 are beam guide portions for guiding laser beam from the laser beam oscillator 200 to the machining head 201. At a position near the laser beam oscillator 200, a reflecting mirror 205a is located, at an end portion of the beam guide portion 203, reflecting mirrors 205b, 205e are located, in an inside of the beam guide portion 203, reflecting mirrors 205c, 205d are located so as to face both reflecting mirrors 205b, 205e, at a position facing the reflecting mirror 205e, a reflecting mirror 205f is located, and at a position facing the reflecting mirror 205f, a reflecting mirror 205g is located on the side of the beam guide portion 204. With this structure, laser beam L generated by the laser beam oscillator 200 is reflected by the reflecting mirrors 205a, 205b, 205c, 205d, 205e, 205f, and 205g in this order so as to reach the machining head 201. The reflecting mirrors 205c, 205d are supported by a block 206 for adjusting a length of an optical path, and are moved according to quantity of movement of the machining head 201, so that the length of the optical path from the laser beam oscillator 200 to the machining head 201 is maintained to be almost constant.
Although quality of machining can be maintained to be constant if the length of the optical path from the laser beam oscillator 200 to the machining head 201 can be made almost constant, the shorter the length of the optical path is, the better the quality of machining is. That is, the shorter and almost constant length of the optical path is, good.
In such a laser beam machine, at least two reflecting mirrors 205e, 205f are located between "the reflecting mirror 205d for adjusting a length of an optical path" and "the reflecting mirror 205g on the beam guide portion 204 side", and laser beam reaches the beam guide portion 204 after taking a long path as shown with an arrow A. Then, the length of the optical path of laser beam becomes longer due to taking a long way, so that a quality of machining decreases.
Besides, it is necessary to seal the beam guide portions 203, 204 so as not to enter dusts and the like therein. When using bellows for sealing, the bellows is easy to be damaged due to repetitive driving, and the durability is low.
Then, a laser beam machine for preventing deterioration of quality of machining by making a length of an optical path of laser beam short and almost constant is still desired. Besides, a laser beam machine having superior durability is still desired.


A fitting is provided for a high purity gas system. The fitting includes first and second components having fluid passageways extending therethrough. Each of the first and second components includes a sealing face having a toroidally generated sealing bead extending unitarily thereabout. At least one nut is provided for urging the sealing faces toward one another. A metallic gasket is disposed between the respective sealing faces. The gasket includes opposed surfaces having annular grooves formed therein. The grooves are dimensioned such that a radially inner circumferentially extending surface on each groove engages a radially inner circumferentially extending surface on a respective toroidal sealing bead. As a result, dead spaces between the fitting and the gasket are eliminated. Additionally, any debris generated as the toroidal sealing beads slide over the gasket are urged outwardly and away from the fluid passages.

This application claims priority on Provisional Appl. No. 60/015,926, filed Apr. 22, 1996.
1. Field of the Invention
The subject invention relates to a metal gasket for a fitting in a high purity gas line.
2. Description of the Prior Art
Gaseous fluids are used in many manufacturing processees, including the manufacture of microprocessors and other electric components. Gases are also used in various chemical engineering processees, in medical applications and in machining or welding operations. The required gas may vary from one industrial application to the next.
Purity of the specified gas often is critical to the manufacturing process. Thus, it is important to prevent the diffusion or leakage of atmospheric contaminants through the gas delivery system and into the gas stream.
A prior art fitting for high pressure fluid applications is shown in FIG. 1 and is identified generally by the numeral 10. This prior art fitting 10 includes a first component 12 with a generally tubular wall 14 defining a fluid passage 16 extending axially therethrough. The first component further includes an enlarged axial end 18 having a shoulder 20 facing the tubular wall 14 of the first component and an opposed sealing face 22. A toroidally generated bead 24 is unitarily defined on the sealing face 22 and is concentric with the fluid passage 16 through the first component 12.
The prior art fitting further includes a second component 32 with a tubular wall 34 and a fluid passage 36 extending axially therethrough. The second component 32 includes an axial end 38 with an annular shoulder 40 facing the tubular wall 34 of the second component 32 and an opposed sealing face 42. The sealing face 42 of the second component 32 includes a toroidally generated bead 44 dimensioned and configured for registration with the toroidal bead 24 on the sealing face 32 of the first component 12.
The prior art fitting further includes male and female coupling nuts 46 and 48 having portions dimensioned and disposed for engaging the respective shoulders 20 and 40 of the first and second components 12 and 32 respectively. The threads of the nuts 46 and 48 are dimensioned and pitched for threaded engagement with one another. The threaded tightening of the nuts urges the sealing faces 22 and 42 of the components 12 and 32 toward one another.
The prior art fitting 10 further includes an annular metal gasket 50 disposed between the first and second components 12 and 32 respectively. More particularly, the prior art gasket 50 includes a first sealing face 52 facing the sealing face 22 of the first component 12, a second sealing face 54 facing the sealing face 42 of the second component 32 and a central passage 55 extending therebetween. Tightening of the nuts 46 and 48 urges the toroidal sealing beads 24 and 44 of the first and second components 12 and 32 respectively into tight sealing engagement with the opposed faces 52 and 54 of the gasket 50.
Some prior art gaskets have planar parallel sealing faces that engage with the toroidal sealing beads 24 and 44. However, the prior art gasket 50 shown in FIG. 1 is provided with annular sealing grooves 56 and 58 formed on the respective first and sealing faces 52 and 54. The grooves 56 and 58 are dimensioned to receive the toroidal sealing beads 24 and 44 therein.
The prior art grooved gasket as shown in FIG. 1 offers several advantages over the prior art gasket with opposed planar sealing faces. For example, the grooves 56 and 58 on the seal faces 52 and 54 on the gasket 50 are recessed in such a way that they are less likely to be damaged by dents or scratches generated during the production, transport, and handling of the gaskets.
The grooved gasket also has provided more than one location at which a pressure tight seal may be established between the toroidal sealing beads 22 and 42 of the components 12 and 32 and the recessed grooves 56 and 58 of the gasket 50. In particular, the toroidal sealing beads 24 and 44 initially contact radially outer portions 64 and 74 of the grooves 56 and 58. However after sufficient tightening, the toroidal sealing beads 24 and 44 may slide into sealing contact with other surfaces of the prior art gasket 50. This reduces the chance that a localized defect on either the gasket 50 or the toroidal sealing bead 24 or 44 will result in a joint leak. In particular, even if a defect extends across one of the circular bands of contact between the gasket 50 and the toroidal sealing bead 24 or 44, the other circular band of contact may remain uncompromised.
Another advantage of the prior art groove gasket can be explained more clearly with reference to FIG. 2. In particular, the prior art toroidal sealing beads 24 and 44 have been dimensioned to engage a radially outer sloped surface 64, 74 leading into the respective grooves 56 and 58. A given amount of axial force applied to the components as the joint is tightened will result in a sealing load, designated as force per inch of seal circumference, that is higher than the seal load which results when a gasket surface that is normal to the axis of the joint contacts a toroidal sealing bead. This increased sealing load makes a tight joint easier to achieve and/or more likely to occur if the parts are tightened to a constant torque. Specifically, a higher sealing force will produce more gasket deformation. If the nut used to tighten the joint is rotated through a constant angle, less torque will be required to achieve this angle of rotation.
With a flat gasket, there is almost no radial motion or relative sliding of the gasket and toroidal sealing bead contact circle as the joint is tightened. However, the prior art alignment of the toroidal sealing bead 24, 44 with radially outer portions 64, 74 of the grooves 56, 58 causes the gasket 50 and the toroidal sealing beads 24, 44 to slide over each other as the sealing load increases. If a soft metallic coating, such as silver plating, is applied to the gasket faces, the sliding contact between the seal surfaces is likely to push a displaced surface layer away from the area of highest contact pressure. This results in the filling of minor scratches, pits and other depressions which might otherwise cause a leaky joint by bridging the narrow zone of contact characteristic of toroidal all-metal base seal joints.
Another advantage of prior art grooved gasket 50 relates to the ability of the gasket 50 to aid in locating the central aperture 55 concentrically to each of the toroidal sealing beads 24 and 44 with which the gasket 50 mates and in locating the components 12 and 32 having the toroidal sealing beads 24 and 44 concentrically with one another. This is helpful in avoiding a partial misalignment of the gasket 50 into an eccentric position where the gasket 50 partly blocks the through passages 16 and 36 through the components 12 and 32.
Finally, the prior art grooved gasket 50 localizes the areas on the gasket 50 at which contact with toroidal sealing beads 24 and 44 may be made. As a result, the areas of the gasket that must be inspected for defects is substantially reduced, thereby facilitating the inspection process.
A disadvantage of the prior art grooved gaskets has been the creation of a dead zone that is substantially isolated from the main flow path as indicated by the cross-hatching in FIG. 3. This creates a situation detrimental to the achievement and maintenance of conditions required for chemical and manufacturing processees that are dependent on high levels of purity, low levels of moisture, freedom from crevice corrosion and an ability to be sterilized or decontaminated.
Additionally, the prior art grooved gasket 50 shown in FIGS. 2 and 3 results in the toroidal sealing beads 24, 44 sliding along the sloped radially outer surfaces 64, 70 of the grooves 56, 58 as the coupling is tightened. This sliding generates debris in the form of small particles of metal. These small particles of metal will be at the axial extreme of the sliding movement, which, in the prior art shown in FIGS. 2 and 3 also is at the radially inner most region of sliding contact. Metal debris separated as the fitting is tightened and as the surfaces slide relative to one another can work their work through the cross-hatched dead area of FIG. 3 and into the gas stream. These metallic components are contaminants that may be unacceptable in many high purity installations, such as installations used in the semi-conductor industry.

High purity gas fitting with grooved gasket


A shower rod mounting assembly is provided with a flexible substrate having a first side and a spaced apart second side. A reversible dry adhesive layer at least partially covers the first side of the substrate to attach the flexible substrate to a surface and leave the underlying surface unmarked after removal. The reversible adhesive retains an adhesion property for a plurality of adhesion cycles. A receptacle is mounted to the second side and is adapted to receive an end of a shower rod. A boss extends from the substrate with a track formed therein with an opening to receive an end of a shower rod. A biasing member extends from the substrate adjacent to the opening to retain the end of the shower rod after installation.

Conventional shower rod assemblies for supporting a shower curtain are mounted to a pair of support surfaces with fasteners. Mechanical fasteners damage the support surfaces during installation. Further damage may be caused during removal, particularly if an excessive load is inadvertently applied to the shower rod assembly. The mechanical fasteners provide limited flexibility. If inadvertently installed incorrectly, movement of the shower rod assembly to another location results in exposed holes formed in the support surface, which may include tiles that are difficult and costly to repair.
Adhesive mount shower rod assemblies use traditional pressure sensitive adhesives which typically contain both a foam layer and an adhesive layer in order to conform to the surface of interest. These assemblies use substantially rigid flanges or mounting plates such as zinc die-cast, stamped steel or injection molded plastic. Once installed these systems are difficult to remove. Additionally, the adhesive leaves behind a significant amount of adhesive residue and foam, requiring harsh chemicals to clean the surface.
Length adjustable or telescopic shower rods are known in the industry. Some are mounted into mounting assemblies with fasteners described above. Some are provided with elastomeric fittings at each end for contacting the support surfaces. The adjustable shower rods are expanded to engage the support surfaces such that the shower rod is in compression to employ friction for maintaining the installation of the shower rod. The compression of the shower rod may be provided by a threaded engagement between concentric rods, a spring or the like. Such adjustable shower rods, may become inadvertently uninstalled due to exposure to steam that may reduce friction at the mounting surface, or fatigue of the spring over time.


An antenna system includes an antenna transmitting and receiving a signal; a power feeding line feeding electric power to the antenna; and a metal conductor ground electrically connected to the power feeding line. Further, the metal conductor ground includes an electromagnetic bandgap.

An electromagnetic bandgap can be implemented by periodically arranging desired unit cells on an electric conductor by a preset interval or without the preset interval therebetween, and on the surfaces of arrangements of the unit cells, tangent component of a magnetic field becomes '0' (zero) at a specific band so that an electric current cannot flow on the surfaces of the electromagnetic bandgap. This feature is a concept opposite to that of an electric conductor and is related to a magnetic conductor, and the surfaces of the electromagnetic bandgap, i.e., the surfaces of the arrangements of the unit cells becomes a high impedance surface in view of an electric circuit. Since a feature of a theoretical magnetic conductor, which cannot exist in real situation, is implemented on the surfaces of the electromagnetic bandgap, the theoretical magnetic conductor is known as an artificial magnetic conductor. This structure, in the field of optics, originally coming from photonic bandgap technology invented to prevent an optical wave from advancing at a specific bandwidth in a guided structure, is recently known as an electromagnetic bandgap for a microwave frequency band as a frequency band to which the structure may be applied is becoming more broad, and is chiefly applied to various fields such as an antenna, a filter, a waveguide, and the like.
Since the electromagnetic bandgap is mostly applied to the antenna field, the electromagnetic bandgap can be understood well by an example of an antenna. Generally, in order to radiate electromagnetic waves effectively, an antenna parallel to a ground of an electric conductor requires a distance longer than λ/4 (λ is a wavelength at a resonance frequency) from the ground. When the distance between the antenna and the ground of the electric conductor is shorter than λ/4, since a surface current is induced on a surface of the ground of the electric conductor in the direction opposite to a current flowing in the antenna, the currents cancel each other so that the antenna cannot radiate electromagnetic waves. However, when the electromagnetic bandgap is applied instead of the ground of the electric conductor, since the surface current can be prevented from flowing on surfaces of the electromagnetic bandgap at a specific bandwidth, the antenna can be operated at a position much nearer than that of the antenna on the electric conductor. Thus, the distance from the ground to the antenna can be reduced so that the antenna can be made small.
Since the electromagnetic bandgap interrupts the surface current at a specific bandwidth, undesired radiation of electromagnetic waves generated from an edge of a finite ground due to the surface current can be reduced. Since the electromagnetic waves radiated from the antenna to the ground side are reflected at the same phase as that of electromagnetic waves directly radiated in the opposite direction by the electromagnetic bandgap, back radiation can be reduced and radiation gain in a main beam direction can be improved.
Since the above-described technical features of the electromagnetic bandgap are mainly applied to planar antennas, the electromagnetic bandgap is recently being widely applied as a solution for a small antenna, and for improving isolation characteristics between antennas and radiation characteristics of the electromagnetic waves.
However, the electromagnetic bandgap is not being applied to a base station antenna, a repeater antenna, a satellite-tracking antenna, a vehicle antenna, and the like, yet.

Antenna system having electromagnetic bandgap

Electronics and Telecommunications Research Institute


Disclosed are an LED lighting apparatus and a control circuit thereof which controls illumination of a lamp including LEDs using a dimmer. The LED lighting apparatus includes a flicker control unit which provides a control signal corresponding to a rectified voltage having a low angle corresponding to a preset low angle region and equal to or less than a preset level or detects an initial abnormal waveform diagram of the rectified voltage and provides a control signal corresponding to the abnormal waveform period, and controls a current path for light emission of the lamp.

According to the recent trend of lighting technology, an LED has been employed as a light source, in order to reduce energy.
A high-brightness LED is differentiated from other light sources in terms of various aspects such as energy consumption, lifetime, and light quality.
However, since the LED is driven by a current, a lighting apparatus using the LED as a light source requires a large number of additional circuits for current driving.
In order to solve the above-described problem, an AC direct-type lighting apparatus has been developed.
The AC direct-type LED lighting apparatus generates a rectified voltage using a commercial AC power supply and drives an LED. Since the AC direct-type LED lighting apparatus directly uses the rectified voltage as an input voltage without using an inductor and capacitor, the AC direct-type LED lighting apparatus has a satisfactory power factor.
A general LED lighting apparatus is designed to be driven through a voltage obtained by rectifying commercial power having an AC voltage.
A lamp of the LED lighting apparatus includes a large number of LEDs connected in series to each other, and controls the LEDs connected in series to emit light using the rectified voltage.
Recently, the LED lighting apparatus has employed a dimmer using a triac, in order to control brightness. The dimmer is generally used to control the brightness of an incandescent lamp.
When the dimmer is applied to the LED lighting apparatus, there may occur a difference between a design value of the LED lighting apparatus and the characteristic of the triac used as a part of the dimmer.
The triac of the dimmer has a holding current which may be changed in response to the characteristic difference. Thus, when a low-angle rectified voltage is provided to the LED lighting apparatus employing the dimmer including the triac, an insufficient level thereof may cause a flicker.
Furthermore, according to the characteristic and use environment of the triac included in the dimmer, a rectified voltage having an abnormal waveform may be inputted to the lamp at the initial stage.
When the rectified voltage having an abnormal waveform is inputted to the lamp, a flicker may occur in the initial state where the LED lighting apparatus is driven.
The conventional LED lighting apparatus must reduce the occurrence of the flicker, in order to perform the brightness control function using the dimmer including the triac.

LED lighting apparatus and control circuit thereof


A valve stem sealing device used for preventing oil from entering a combustion chamber through a gap formed between a valve guide and a valve stem is disclosed. The valve stem sealing device comprises an annular oil seal surrounding a valve stem and an annular support member fixed to the top of the valve guide so as to hold the oil seal in its place, wherein the support member has an inwardly opening annular recess and rotatably receives the oil seal in the recess, with a bearing being positioned between said oil seal and the side wall of the support member. In addition, a rubber member is tightly interposed between the support member and the valve guide so as to absorb the vibrations caused by a valve operation. Also, a support cap covers the outside wall of the oil seal so that the outside wall of the support cap is brought into contact with the bearing.

1. Field of the Invention
The present invention relates, in general, to a valve stem sealing device used for preventing oil from entering a combustion chamber through a gap formed between a valve guide and a valve stem and, more particularly, to a valve stem sealing device with an oil seal being capable of rotation with the valve stem, thereby preventing the oil seal from being abraded and the oil from entering the combustion chamber.
2. Description of the Prior Art
As well known to those skilled in the art, an intake valve is mounted to an internal combustion engine, thus allowing a mixed fuel to flow into a combustion chamber. Also, the engine has an exhaust valve for exhausting combustion gas into the atmosphere.
FIG. 2 shows the construction of one typical valve, which may be an intake or an exhaust valve for internal combustion engines. It is important to note that the two valves are the same construction.
As shown in FIG. 2, a port 3 of a combustion chamber is opened or closed by the reciprocating motion of the valve which is driven by the rotating motion of a cam 2. The valve stem 12 of the valve 10 vertically reciprocates under the guide of a valve guide 7 of a cylinder head.
The cylinder head, with the cam 2, also has a valve control mechanism. In order to effectively operate both the cam 2 and the valve control mechanism, cooling and lubrication oil is supplied into the cylinder head.
However, the lubrication oil may be unexpectedly introduced into the combustion chamber through a gap formed between the valve guide 7 and the valve stem 12, thus reducing the combustion efficiency of the engine. Furthermore, such an unexpected introduction of oil into the combustion chamber may cause the engine to break down. Thus, it is preferable to mount an oil seal 20 onto the top of the valve guide 7 in an effort to prevent such an introduction of oil into the combustion chamber.
The oil seal 20 is fitted over the valve stem 12, with a support means 22 surrounding the seal 20 so as to hold the seal 20 in its place. The support means 22 is preferably made of a steel plate having a certain thickness. The support means 22 is fixed onto the top of the valve guide 7. The oil seal 20 has an annular blade 20a, which inwardly extends from the inner surface of the seal 20 and comes into close and movable contact with the side wall of the valve stem 12.
Thus, the oil seal 20 removes any gap from the junction between the valve guide 7 and the valve stem 12. That is, the valve stem 12 vertically reciprocates the inside of the oil seal 20, with the annular blade 20a being brought into close contact with the side wall of the valve stem 12, thereby preventing the oil from entering the combustion chamber.
When the valve 10 is reciprocally moved, the valve 10 is somewhat rotated. Also, in the operation of the valve, the valve head 14 comes into repeated contact with the port 3 at a high speed. As a result, the combustion chamber is repeatedly opened or closed by the reciprocating and rotating motion of the valve head 14.
However, in such a valve stem sealing device structure according to the prior art, the annular blade 20a of the oil seal 20 is quickly abraded due to the rotating motion of the valve 10, with the oil seal 20 being fixed to the top the valve guide 7 by the support means 22. Therefore, the typical sealing device may fail to prevent oil from flowing into the combustion chamber. In such a case, the sealing device reduces the combustion efficiency of an engine and, cause the engine to break down.

Device for sensing the amount of oil in oil pans


An aircraft for carrying at least one rigid cargo container includes a beam structure with a forward fuselage attached to the forward end of the beam structure and an empennage attached to the rearward end of the beam structure. Wings and engines are mounted relative to the beam structure and a fairing creates a cargo bay able to receive standard sized intermodal cargo containers. Intermodal cargo containers of light construction and rigid structure are positioned within the cargo bay and securely mounted therein. The beam structure is designed to support flight, takeoffs and landings when the aircraft is empty but requires the added strength of the containers securely mounted to the beam structure when the aircraft is loaded. The aircraft is contemplated to be a drone.

The field of the present invention is cargo aircraft for transporting modular containers.
The basic unit for transporting goods has been the truck. Being the basic unit, the truck has defined limitations on intermodal containers that can typically be transported by ships, trains and trucks. Much of commerce today for which intermodal containers are most convenient are high volume, low weight products, computers being one example. Thus, volume instead of weight creates the limiting factor in the design of intermodal containers. As such, containers have grown to the maximum volume capacity of the basic unit, the truck. As such, intermodal containers are limited by the dimensions allowed by highway infrastructures.
The aforementioned intermodal containers have greatly facilitated and lowered the cost of cargo transportation. However, air cargo has generally been excluded from participation in intermodal cargo systems. Aircraft of a size capable of carrying substantial cargo have typically been designed first as passenger aircraft. Cylindrical fuselages and lack of large access ports thereto in such passenger aircraft limit the use of such aircraft for truly intermodal cargo systems. Rather, the aircraft must become the basic unit with odd shaped and smaller sized containers. As a result, even with containerized cargo, a truck must be loaded with multiple individual containers for efficient distribution of air cargo. Such aircraft are also designed to be efficient at high speeds which is costly. Military transports are also not particularly compatible with intermodel cargo systems as they are designed for oversized cargo such as rolling equipment, e.g., tanks and trucks, and palletized, irregularly shaped cargo. Most aircraft specifically designed for the military also are mission directed and overall efficiency for competitive cargo transportation is not a first priority.
The inability of aircraft to participate in intermodal container cargo systems has been disadvantageous to international commerce. Business principals such as just-in-time supply and changing business environments including rapid global internet communication have created a demand for much more rapid international shipping than can be provided by conventional ships. However, air cargo systems remain both expensive and inconvenient to intermodal shipping.


An isolated antiviral peptide is characterized by the amino acid sequence GDEPLENYLDTEYF and a significant in vitro binding affinity for HIV-1 gp 120 and gp 41 and human CD4 cells. The peptide exhibits anti-retroviral activity in vivo, particularly anti-HIV-1 activity.

Typically, infection with the human immunodeficiency virus, HIV-1, eventually causes acquired immunodeficiency syndrome (AIDS) and an associated syndrome, AIDS-related complex (ARC). Neutralizing this virus has proved difficult, largely because its structure obstructs immune system access to viral epitopes and its genetic material is highly variable. Accordingly, researchers have been seeking prophylactic and therapeutic methods for preventing or controlling HIV which are not dependent upon antibody-mediated immunity.
The HIV retrovirus replicates in certain immune system cells, specifically the CD4+ subset of T-lymphocytes (pre-Th cells arising in the thymus). In the usual course of a cell-mediated immune response to an intracellular pathogen such as a virus, dendritic cells (antigen-presenting cells) carrying antigen fragments and secreted cytokines activate these CD4+ T-cells. Activated cells, called T-helper or Th cells, in turn secrete their own cytokines and stimulate macrophages. CD4+Th cells also propagate cellular immune response by binding chemotactic cytokines (chemokines, CCs) to their CC surface receptors. It is by this route that HIV-1 infection of these cells is enabled because, in addition to binding chemokines, these CC receptors act together with the CD4+ surface glycoprotein as coreceptors for HIV-1 and mediate entry of the virus into the CD4+Th cell. There, the virus usurps the native genetic material for viral replication while destroying cell functions essential for building immunity; the increasing destruction of these cells appears to be responsible for the eventual collapse of the cell-mediated immune system often seen in terminal AIDS patients.
It has been recognized that denying entry into CD4+ cells to the HIV-1 virus could at least slow the progress of the infection and alleviate, if not cure, the disease and/or its symptoms. The complex mechanism by which the virus crosses the cell membrane has been widely investigated. Broadly, the entry of human immunodeficiency virus into, for example, CD4+ Th1 cells (T-helper type 1 cells, is dependent upon a sequential interaction of the gp120/gp41 subunits of the viral envelope glycoprotein gp160 with the CD4+Th1 cell surface glycoprotein and the cell surface receptor CCR5. On binding of gp120 with its cell surface binding sites, a conformational change in the latent gp41 subunit through an intermediate state to an active state is initiated, inducing fusion of the viral and cellular membranes and transport of the virus into the cell (Nature 387:426-30, 1997).
Accordingly, numerous binding experiments have been conducted in an effort to find antiviral ligands that will effectively compete with the HIV-1 for CD4+ gp and/or CCR5 binding sites, or that will preferentially block gp120 and/or gp41 binding domains. In one example, a reported structure (X-ray crystallography) comprising an HIV-1 gp120 core complexed with a two-domain fragment of human CD4 and an antigen-binding fragment of a neutralizing antibody that blocks chemokine-receptor binding, is said to reveal a CD4-gp120 interface, a conserved binding site for the chemokine receptor, evidence for a conformational change on CD4 binding, the nature of a CD4-induced antibody epitope, and specific mechanisms for viral immune evasion, "which should guide efforts to intervene" (Nature 393 (6686):632-1, 1998). Also, it has been shown that inhibition of the change in structure of gp41 from its intermediate to active state with peptides used as competitors for critical cell receptors may reduce viral load, and that while gp120 masks epitopes on the gp41 subunit in its latent state, gp41 may be vulnerable to neutralizing antibodies in its transient or intermediate state (Molecular Membrane Biology 16:3-9, 1999). In another study, disclosed in U.S. Patent Application Publication US 2004/0018639 A1, filed Jun. 3, 2003, published Jan. 29, 2004, by Zhabilov et al. the content of which is incorporated herein in its entirety by reference, a protein designated "Thymus Factor" ("TF") is stated to have the ability to bind to a fragment of HIV-1 gp41 in gel electrophoresis, and that this binding property can be used to assay TF activity or in the treatment of HIV.

Irreversibly-inactivated pepsinogen fragment and pharmaceutical compositions comprising the same for detecting, preventing and treating HIV


A high voltage power supply system includes: a high voltage power supply; a current detector; a voltage detector; a conversion section configured to obtain a converted-current value by dividing a detected-current voltage value by a predetermined resistance value; a selector configured to select one of the detected-current voltage value and the detected-voltage voltage value; a resistance variable section configured to change the predetermined resistance value; a temperature detector; a humidity detector; and a control section configured to create a voltage setting signal, a selection signal, and a resistance variable signal on the basis of the detected-voltage voltage value, the detected-temperature value, and the detected-humidity value, and to apply the voltage setting signal to the high voltage power supply, the selection signal to the selector, and the resistance variable signal to the resistance variable section.

1. Field of the Invention
The disclosure herein relates to a high voltage power supply system that supplies a high voltage to a transfer roller, and an image formation apparatus using the same.
2. Description of Related Art
Japanese Patent Application Publication No. 2003-324954 discloses a conventional high voltage power supply system that includes a transfer roller configured to transfer a toner image formed on a photosensitive drum onto a recording medium, and supplies a voltage to the transfer roller. The high voltage power supply system is configured to change an output voltage in accordance with a changing current value that will flow into the transfer roller, based only on the type of recording medium.

High voltage power supply system and image formation apparatus


A microwave excited ultraviolet lamp system with a data logging and retrieval circuit and method for operating the same. The data logging and retrieval circuit stores operational data in a cache memory using a FIFO data storage protocol. The contents of the cache memory are periodically copied to a larger removable memory so that the removable memory contains a relatively long historical record of the system operational parameters. The data logging and retrieval circuit includes a data port configured to load the contents of the cache memory into an external device when the device is coupled to the data port. A second data port allows the external device to supply power to the data logging and retrieval circuit so that data may be retrieved when the internal power supply is malfunctioning. Data stored in the removable memory may be protected so that it may only be accessed by authorized personnel.

Microwave excited ultraviolet ("UV") lamp systems are commonly used for heating and curing materials such as adhesives, sealants, inks, and coatings, as well as for modifying the surface of an object on a molecular level. Microwave excited ultraviolet lamp systems produce ultraviolet light by exciting an electrodeless plasma lamp with microwave energy. The electrodeless lamp is mounted within a metallic microwave cavity or chamber, and one or more microwave generators, such as magnetrons, are coupled to the interior of the microwave cavity. The magnetrons supply microwave energy to initiate and sustain a plasma in a gas mixture that typically includes mercury and that is enclosed in the electrodeless lamp. In turn, the plasma emits a characteristic spectrum of electromagnetic radiation strongly weighted with spectral lines or photons having ultraviolet and infrared wavelengths.
Microwave-excited ultraviolet light lamp systems typically have one or more power supplies that provide high voltage to each magnetron, as well as lesser voltages to other lamp system components, system control electronics, sensors, and magnetron filaments. The system operational data is used by the power supply to adjust supplied voltages and currents, and may also be monitored by system technicians to assist with system set up and troubleshooting, as well as for diagnosing causes of malfunctioning equipment. However, this type of troubleshooting requires that a technician be on site to monitor the operational data. On site visits to repair, maintain and trouble shoot microwave excited ultraviolet lamp systems may result in significant costs associated with lost productivity during travel time to the site, as well as other travel related expenses. Further, certain types of system failures may cause the operational data to be unavailable for analysis, making diagnosis of the problem more difficult.
Thus, there is a need for microwave excited ultraviolet lamp systems with data logging and retrieval circuits, as well as methods that can provide operational data after system failures and that can be provided to technicians without requiring a site visit.

This patent is subject to a terminal disclaimer.

Microwave excited ultraviolet lamp system with data logging and retrieval circuit and method


A lookup table for searching for a longest prefix match for a key is disclosed. The lookup table provides a match for a key in a single search cycle. The number of matches stored in the lookup table is maximized by storing each match in only one location in the lookup table. The binary tree is divided into a plurality of levels and each level has a plurality of subtrees. A subtree descriptor stored for a subtree includes a field for each node in the subtree. The state of the field indicates whether an entry for the node is stored in the table. The bit vector allows indexing of the single match stored for the key.

The Internet is a set of networks connected by routers. A router maintains a routing table that indicates for each possible destination network, the next hop to which a received data packet should be forwarded. The next hop may be another router or the final destination.
An Internet Protocol ("IP") data packet received at a port in a router includes an IP destination address. The IP destination address is the final destination of the IP data packet. Currently there are two versions of IP, IP version 4 ("IPv4") and IP version 6 ("IPv6"). IPv4 provides a 32-bit field in an IP header included in the data packeted for storing the IP destination address. The router forwards a received data packet connected to a next-loop router, or the final destination if the destination is the local network, dependent on the IP destination address stored in the IP header.
A 32-bit IPv4 destination address provides 4 billion possible routes. An Internet router typically stores 50,000 of the 4 billion possible routes. However, the number of stored routes will increase with the growth of the Internet and the widespread use of IPv6.
Originally, the IP address space was divided into three classes of IP addresses; A, B and C. Each IP address space was divided into a network address and a host address. Class A allowed for 126 networks and 16 million hosts per network. Class B allowed for 16382 networks with 64,000 hosts per network and class C allowed for 2 million networks with 256 hosts per network. However, dividing the IP address space into different classes reduced the number of available IP addresses. Class C only allowed a maximum of 256 hosts per network which is too small for most organizations. Therefore, most organizations were assigned a Class B address, taking up 64,000 host addresses which could not be used by other organizations even if they were not used by the organization to which they were assigned. Hosts in an organization with a Class B IP address all store the same network address in the 16 Most Significant Bits ("MBSs"), for example, 128.32.xx.xx.
Classless InterDomain Routing ("CIDR") was introduced to free up unused IP host addresses. The remaining unused networks are allocated to organization in variable sized blocks. An organization requiring 500 addresses gets 500 continuous addresses. For example, an organization can be assigned 500 available addresses starting at 128.32.xx. The number of routes stored by a router has increased since the introduction of Classless InterDomain Routing. Classless InterDomain Routing requires longest prefix matching to find the corresponding route instead of searching for a matching network address in order to find the corresponding next hop for the IP destination address. For example, a search can no longer stop after the 16 MSBs of a Class B IP address, for example, 128.xx.xx because 128.32.4.xx may be assigned to another organization requiring a different next hop.
One method for searching for a longest prefix match for a key is through the use of a binary tree search. A binary tree search matches a 32-bit input bit by bit down to 32 levels, requiring 32 searches to find the entry matching the 32-bit key. Another method for searching for a match is through the use of a Patricia tree. A Patricia tree reduces the number of searches required if there are no entries down a leaf of the binary tree.
Yet another method for efficiently searching for a next hop associated with an IP destination address is described in PCT application Serial Number PCT/SE98/00854 entitled "Method and System for Fast Routing Lookups" by Brodnick et aL filed on May 11, 1998. The method described by Brodnick reduces the number of next hops stored by not storing duplicate routes. By reducing the number of next hops, the memory requirement is reduced so that a route lookup table can be stored in fast cache memory.
Brodnick et al. divides the binary tree into 3-levels. Dividing the binary tree into 3-levels reduces the number of searches to three. The indexed entry in the first level indicates whether the search can end at the first level with the route taken from the entry, or the search must continue to a subsequent level using a further portion of the IP destination address.
FIG. 1A illustrates a prior art 64K (65536) bit map representing the first level of a binary tree. A 64K bit map 30 represents the leaves or nodes 44 of the binary tree at depth 16, with one bit per node 44. The bit map is divided into bit-masks of length 16. There are 212=4096 bit masks in the 64 k bit map. One bit mask is shown in FIG. 1A. A bit in the bit map 30 is set to '1' if there is a subtree or a route index stored in an array of pointers corresponding to the node 44. A bit in the bit map 30 is set to '0' if the node shares a route entry with a previous node 44.
A bit is set in the bit map 30 if the node does not share the route entry the previous node 44. Bit 4 is set '1' indicating that there is a subtree or route index corresponding to the node 44. Bit 5 is set '0' indicating that the node corresponding to bit 5 shares the subtree or route index with the node corresponding to bit 4. Bit 6 is set '1' indicating that the node corresponding to bit 6 does not share a subtree or route index with bits 4 and 5. Bit 6 corresponds to a node sharing the default route. Bits 6 and 12 set to '1' correspond to the default route.
FIG. 1B illustrates a prior art lookup table implemented in cache memory. The lookup table includes an array of code words 36, an array of base indices 34 and a map table 40. A 32-bit IP address 38 is also shown in FIG. 1B. A codeword 46 is stored in the array of code words 36 for each bit mask in the bit map 30 (FIG. 1A). The code word 46 includes a six-bit value 46a and a 10-bit offset 46b. A base index 42 is stored in the array of base indices 34 for every four code words 46 in the array of code words 36.
The array of code words 36, array of base indices 34 and map table 40 are used to select a pointer in an array of pointers (not shown). The pointer stores a route index or an index to perform a further search.
A group of pointers in the array of pointers is selected by selecting a code word 46 in the array of code words 36 and a base index 42 in the array of base indices 34. The code word 46 is selected using the first 12 bits 50 of the IP address 38. The base index 42 is selected using the first 10 bits 48 of the IP address 38. The correct pointer in the group of pointers is selected using the map table 32.
The 10-bit value 46b in the selected code word 36 is an index into the map table 32. The map table 32 maps bit numbers within a bit-mask to 4-bit offsets. The offset specifies the pointer within the selected group of pointers in the array of pointers. The 10-bit value 46b selects the row in the map table 32 and bits 19:16 of the IP address 52 selects the 4-bit offset 54.
An offset to specify a pointer is stored in the map table 32 for each '1' stored in the bit mask 30 (FIG. 1A). Thus, two separate location offsets to specify a default pointer corresponding to bits 6 and 12 in the bit mask 30 are stored in two separate locations in the map table 32. Storing multiple copies of the default pointer in the array of pointers reduces the number of route indexes that can be stored in a fixed size memory.
FIG. 2A illustrates a worst case encoded subtree which requires twice the number of entries in the array of pointers than actual routes. The routes r1-r8 are assigned to leaf nodes 215, 217, 219, 221, 223, 225, 227 and 229 as follows: r1 to leafnode 215; r2 to leaf node 217, r3 to leaf node 219; r4 to leaf node 221; r5 to leaf node 223; r6 to leaf node 225; r7 to leaf node 227 and r8 to leaf node 229. The default route r0 is assigned to all of the other leaf nodes 216, 218, 220, 222, 224, 226, 228 and 230.
FIG. 2B illustrates a prior art bit map 30 and associated pointers stored in an array of pointers 50 representative of the subtree shown in FIG. 2A. As described in conjunction with FIG. 1A, the bit map 30 includes one bit 2421-24216 for each leaf node in the subtree. The array of pointers 50 stores a pointer for each bit set to '1' in the bit map 30. A bit is set '1' to indicate that the route corresponding to the leaf node differs from the route stored for the previous leaf node in the map table 32.
Sixteen entries are used to store the eight pointers to routes r1-r8 and the default route r0. The pointer to the default route r0 is stored in eight of the sixteen entries 2521-16.
A route corresponding to a node in the subtree is found by counting the number of '1's in the bit map and incrementing the pointer by the total number of ones. For example, the entry corresponding to node 224 (FIG. 2A) is stored in entry 25212. Storing the pointer to the default route in eight different entries decreases the available memory for storing pointers to routes.


A mobile terminal and controlling method thereof are disclosed, by which a user interface for appreciating a 3-dimensional (3D) stereoscopic image more conveniently can be provided. The present invention includes a display unit including a parallax generating means for displaying a 3D stereoscopic image on at least one portion of the display unit and a controller, when a planar (2D) image is displayed via the display unit, determining whether the 3D stereoscopic image is outputted via the display unit within a preset duration, the controller, if the 3D stereoscopic image is outputted as a result of the determination, controlling a prescribed visual effect indicating that the 3D stereoscopic image is outputted to be given to at least one region of the display unit.

1. Field
The present invention relates to a mobile terminal, and more particularly, to a mobile terminal and controlling method thereof. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for providing a user interface for appreciating a 3-dimensional (3D) stereoscopic image more conveniently.
2. Background
Generally, terminals can be classified into mobile/portable terminals and stationary terminals. The mobile terminals can be classified into handheld terminals and vehicle mount terminals again according to possibility of user's direct portability.
As functions of the terminal are diversified, the terminal is implemented as a multimedia player provided with composite functions such as photographing of photos or moving pictures, playback of music or moving picture files, game play, broadcast reception and the like for example.
To support and increase of the terminal functions, it may be able to consider the improvement of structural parts and/or software parts of the terminal.
Recently, since a 2-dimensional (hereinafter abbreviated 2D) image and a 3-dimensional (hereinafter abbreviated 3D) image can be selectively implemented on a display unit of a terminal, the demands for a user interface for appreciating a 3D stereoscopic image more conveniently are ongoing to rise.

Mobile terminal to display a perceived 3D image and control method thereof


A gas turbine engine with a compressor rotor having compressor impulse blades that delivers gas at supersonic conditions to a stator. The stator includes a one or more aerodynamic ducts that each have a converging portion and a diverging portion for deceleration of the selected gas to subsonic conditions and to deliver a high pressure oxidant containing gas to flameholders. The flameholders may be provided as trapped vortex combustors, for combustion of a fuel to produce hot pressurized combustion gases. The hot pressurized combustion gases are choked before passing out of an aerodynamic duct to a turbine. Work is recovered in a turbine by expanding the combustion gases through impulse blades. By balancing the axial loading on compressor impulse blades and turbine impulse blades, asymmetrical thrust is minimized or avoided.

A continuing interest exists in industry for improved gas turbine engines. For many reasons, gas turbine engines continue to be useful in a wide variety of applications. Operational costs could be substantially improved in many applications by adoption of an improved gas turbine engine that would increase operating efficiency as compared to currently utilized gas turbine designs. Further, from the point of view of maintenance costs, it would be desirable to develop improved gas turbine engine designs that reduce the mass of rotating components, since such rotating components are comparatively costly when replacement or repair becomes necessary, as compared to non-rotating parts, which although subject to stress and strain from temperature and pressure, are not subject to additional loads due to rotary motion. Thus, it can be appreciated that it would be advantageous to provide a new, high-efficiency gas turbine design which minimizes moving parts. Generally, it would be advantageous to provide more horsepower with less weight. And more specifically, it would be advantageous to provide small gas turbines having a relatively high overall efficiency, particularly in the one-half to three megawatt range.
Components of gas turbine engines include a compressor, a combustor, a nozzle or choke, and a turbine. Although supersonic compressors have been contemplated for use in gas turbine engines, in so far as we are aware, there remain various technical problems in the field and with respect to which better solutions are required in order to improve operational capability and compression efficiency. In particular, although relatively low pressure ratio supersonic compressors have been proposed for gas turbine engines, there still remains a need for gas turbine engines that can be easily started, yet be operated at high compression ratios. Further, it would be advantageous to avoid configurations that present moving shocks, such as between moving blades, or between moving and fixed blades, or between moving blades and fixed walls, in order to more simply achieve stability for normal shock location in the compressor of a gas turbine engine. Further, new designs that might reduce or minimize mechanical issues such as axial thrust loading and the requirement for expensive bearings and related equipment, would be desirable.
Although a variety of gas turbine engines with supersonic compressors have been contemplated, the work of G. F. Hausmann as reflected in U.S. Pat. No. 2,947,139, issued Apr. 2, 1960, and entitled By-Pass Turbojet is instructive of such work generally, and thus is suggestive of technical problems that remain in the field and with respect to which better solutions are required in order to improve operational capability and compression efficiency. The Hausmann patent describes the use of counter-rotating impulse blade rotors (or a single rotor in another embodiment) with a downstream stator, combustor, and convergent/divergent exhaust nozzle. However, that device is directed at aircraft propulsion applications. Flow is maintained substantially axially, with attendant losses. And, like other prior supersonic compressor designs, the design does not address minimization of the total "wetted area"—including the leading edges subject to bow wave shock losses which result in loss of efficiency. And, although the Hausmann patent suggests "high pressure" ratios, the pressure ratios noted therein are quoted as being "6 or 7 with adiabatic efficiencies which approach multi-stage subsonic compressors."
In short, there remains a need to provide a design for a high pressure ratio—such as in excess of seven to one (7:1), or even twice that, or more—in a supersonic compressor that simultaneously resolves various practical problems seen in previous designs. Such problems include (a) providing for starting of a compressor designed for high pressure ratio operation so as to control a normal shock wave at an effective location in a supersonic diffuser designed for high pressure ratio and efficient compression, (b) avoiding excessive numbers of leading edge structures (such as may be encountered in prior art multi-bladed stators), and minimizing other losses encountered by a high velocity supersonic gas stream upon entering a diffuser, and (c) providing for effective boundary layer control, especially as related to retention of a normal shock at a desirable location, in order to achieve high compression ratios in an efficient manner. Further, improvements in overall power to weight ratio (that is, providing power in a small, compact package), and in overall cycle efficiency (thus improving fuel economy), would be a distinct advantage in many, if not most applications.


A method for allowing native, functional, and test configurations of a memory to be independent of one another includes steps as follows. A memory is first provided. The memory has a native configuration including k words and n data output pins, k and n being positive integers. Each of the k words has a width of n bits. Then the n data output pins are connected to a programmable multiplexer for multiplexing the n data output pins into at least one group of data output pins of the programmable multiplexer. Each of the at least one group of data output pins has no more than n data output pins and is suitable for enabling the memory to have at least one of a test configuration or a functional configuration. At user's discretion, the test configuration may or may not have a width of n bits, the functional configuration may or may not have a width of n bits, and the test configuration and the functional configuration may or may not have the same width.

In semiconductor devices such as RapidChip™ developed by LSI Logic Corp., and FPGAs (Field Programmable Gate Arrays), it is often desired to provide flexibility to change the size of a memory and also reduce the overall test cost of the memory without adding significant performance penalty and area. Conventionally, this is performed using external muxing (i.e., multiplexing) in standard cells. However, there is no scheme available to reduce the test overhead. In addition, external muxing in standard cells is not acceptable because it takes a significant area and causes significant performance penalty. Moreover, the cost of BIST (Built-In Self-Test) per memory is also significant because the memory sizes themselves are kept very small and wide to support a wide range of configurations. This also creates an inefficient test organization and implementation.
Thus, it is desirable to have a method and apparatus to provide flexibility in memories and also reduce the overall test cost without adding significant performance penalty and area.

Method and apparatus for separating native, functional and test configurations of memory


A combination of a die lubricant source, a feedtube, and a nozzle assembly, as well as a method of using the combination to cool and/or lubricate a die. The die lubricant source supplies a plurality of bursts of a metered amount of a die lubricant to a feedtube bore. The nozzle assembly includes a removable barrel having a barrel bore therethrough and a removable atomizing spray tip having a spray tip bore therethrough. A posterior end of the barrel bore communicates with the feedtube bore and an anterior end of the barrel bore communicates with the spray tip bore. The ratio of the cross-sectional area of the barrel bore divided by the cross-sectional area of the spray tip bore is not less than 2.5, and the cross-sectional area of the barrel bore is preferably not greater than the cross-sectional area of the feedtube bore. The nozzle assembly atomizes and delivers the plurality of bursts of the metered amount of the die lubricant so that substantially none of the die lubricant drips from the nozzle assembly following each one of the bursts of the metered amount of the die lubricant. The method includes using the spray nozzle so that a steam barrier, created by contact of a previous lubricant burst with the die, is allowed to dissipate before creating a successive burst of the metered amount of the die lubricant.

1. Field of the Invention
The present invention relates, in general, to a spray nozzle assembly, and in particular, to a die lubricant spray nozzle assembly which can be used to atomizingly spray a plurality of short bursts of a metered amount of die lubricant without substantial dripping.
2. Information Disclosure Statement
It is often desirable to apply a die lubricant to a die of a die press and/or to the workpiece being processed.
In many prior art air-driven die lubricant systems, the die lubricant is atomized by mixing compressed air with the die lubricant in an atomizing chamber, and the air and lubricant mixture is then directed through a spray tip, on a continuous-feed basis, to the die and/or the workpiece. A large volume of compressed air, having a high velocity, is typically used in the prior art to atomize the die lubricant into fine particles. Because the velocity of the air and die lubricant mixture is so great as it passes through the spray tip and contacts the die, a large volume of the die lubricant typically bounces off of the die and the workpiece. This causes inefficient utilization of the die lubricant, and the accumulation of this reflected die lubricant in the work area causes an environmental and safety hazard. Additionally, a large percentage of dies operate in excess of 500 degrees Fahrenheit (260 degrees Celsius), and it has been experimentally found that when die lubricant contacts a die operating in excess of 500 degrees Fahrenheit (260 degrees Celsius), a steam barrier is generated that acts to repel the die lubricant from the die and the lubricated workpiece. The velocity of the die lubricant must therefore be increased in order to penetrate this steam barrier, and this increased velocity causes a still-greater volume of die lubricant to bounce off of the die and workpiece. The result is an increased inefficiency in the utilization of the die lubricant and an increased environmental and safety hazard in the work area.
Even when airless prior art nozzle assemblies are used to atomize bursts of die lubricant, they do not atomize the die lubricant to the extent desired and produce lubricant drip following each short burst of a metered amount of the die lubricant. Similar to the effect observed with air-driven prior art nozzle assemblies, a steam barrier is generated when the die lubricant contacts a die operating in excess of 500 degrees Fahrenheit (260 degrees Celsius), thereby creating a problem of repulsion of the next short burst of the metered amount of die lubricant.
It is therefore desirable to have a lubricant driven system having an improved die lubricant spray nozzle assembly that can deliver a plurality of short bursts of a precisely metered amount of die lubricant while substantially eliminating the problem of die lubricant drip following each one of the bursts, and that can also provide significant atoniization of the die lubricant as it exits the nozzle assembly. It is also desirable to have a method of using the nozzle assembly which will eliminate the problem of die lubricant repulsion associated with the creation of a steam barrier.
A preliminary patentability search in Class 239 subclasses 533.1, 568, 575, 590, 597, 598, and 599 and in Class 164 subclass 72, produced the following patents, some of which may be relevant to the present invention: Gigantino et al., U.S. Pat. No. 3,510,065, issued May 5, 1970; Heron et al., U.S. Pat. No. 4,878,785, issued Nov. 7, 1989; Bendig et al., U.S. Pat. No. 4,989,788, issued Feb. 5, 1991; and Herstek et al., U.S. Pat. No. 5,288,027, issued Feb. 22, 1994. Gigantino et al. discloses a nozzle having a non-atomizing spray tip that is designed to deliver a continuous spray of water having a high pressure, 1800 to 3000 pounds per square inch, at a high velocity. Heron et al. discloses a nozzle that is designed to continuously deliver an abrasive fluid at a high velocity and to direct the abrasive fluid towards the center of an internal cross-sectional area of the nozzle in order to reduce wear of the internal cross-sectional area, and the nozzle is designed to have an elongated non-atomizing spray tip.
The inventor is also aware of the following related reference that may be relevant to the present invention: Hayes, U.S. Pat. No. 5,531,085, issued Jul. 2, 1996, which describes a die lubricant applicator for delivering precisely metered bursts of die lubricant.
None of these references, either singly or in combination, disclose or suggest the present invention.


A detector array including a plurality of scintillators for use in association with an imaging device. The detector array is provided for accurate determination of the location of the impingement of radiation upon an individual scintillator detector. An air gap is disposed between the scintillator elements, thereby increasing the packing fraction and overall sensitivity of the array. The amount of light transmitted down the scintillator element and the amount of light transmitted to adjacent elements is modified to optimize the identification of each element in a position profile map by adjusting the surface finish of the detector elements.

1. Field of Invention
This invention pertains to a method for fabricating a detector array for use in imaging applications such as X-ray imaging, fluoroscopy, positron emission tomography (PET), single photon emission computed tomography (SPECT), computed tomography (CT), gamma camera and digital mammography systems. More particularly, the present invention provides a simple and highly effective detector array design and its fabrication with high packing fraction resulting in greater sensitivity while still maintaining spatial resolution.
2. Description of the Related Art
In the field of imaging, it is well known that imaging devices incorporate a plurality of scintillator arrays for detecting radioactivity from various sources. It is also common practice, when constructing scintillator arrays composed of discrete scintillator elements, to pack the scintillator elements together with a reflective medium interposed between the individual elements creating photon boundaries. Conventionally the reflective medium serves to collimate the scintillation light along the crystal element into a light guide to accurately assess the location at which the radiation impinges upon the detector elements. The reflective medium further serves to increase the light collection efficiency from each scintillator element as well as to minimize the cross-talk, or light transfer (transmission of light), from one scintillator element to an adjacent element. Reflective mediums include reflective powders, film, paint, adhesives doped with reflective powders or a combination of materials.
Conventionally, scintillator arrays have been formed from polished or rough crystals that are either: hand-wrapped in reflective PTFE tape and bundled together; glued together using a white pigment such as BaSO4 or TiO2 mixed with an epoxy or RTV; or glued to a glass light guide with defined spacing and afterwards filled with reflective material as discussed above.
Another approach utilizes individual reflector pieces that are bonded to the sides of the scintillator element with the aid of a bonding agent. This process requires iterations of bonding and cutting until a desired array size is formed.
Other devices have been produced to form an array of scintillator elements. Typical of the art are those devices disclosed in the following U.S. Patents:
U.S. Pat. No.Inventor(s)Issue Date3,936,645A. H. IversonFeb. 3, 19764,749,863M. E. CaseyJun. 7, 19884,914,301Y. AkaiApr. 3, 19904,982,096H. Fujii et al.Jan. 1, 19915,059,800M. K. Cueman et al.Oct. 22, 19916,292,529S. Marcovici et al.Sep. 18, 2001
Of these patents, the '645 patent issued to Iverson discloses a radiation sensitive structure having an array of cells. The cells are formed by cutting narrow slots in a sheet of luminescent material. The slots are filled with a material opaque to either light or radiation or both. The '800 patent issued to Cueman et al., discloses a similar scintillator array wherein wider slots are formed on the bottom of the array.
Most of the aforementioned methods require a separate light guide attached to the bottom of the detector array to channel and direct the light in a definitive pattern on to a receiver or set of receivers such as photomultiplier tubes or diodes. This light guide usually contains cuts in varying depths to alter the light pattern on the receivers. In addition the cuts are filled with reflective material as discussed in '863 patent issued to Casey.

Detector array utilizing air gaps as a reflector between array elements


An apparatus for holding a substrate (113) has a chuck cup (101), a seal shell (111), a chuck plate (102) and a vertical driving device (103). The seal shell (111) has a bottom wall (1111), an outer wall (1112) and an inner wall (1114). The inner wall (1114) forms a lip seal portion (1115). The bottom wall (1111) and the outer wall (1112) of the seal shell (111) respectively wrap the bottom surface and the outer surface of the base portion (1011) of the chuck cup (101). The lip seal portion (1115) wraps the supporting portion (1014) of the chuck cup (101) for sealing the edge of the front side of the substrate (113). The apparatus protects the edge of the front side of the substrate, the back side of the substrate and the chuck cup from contacting with the electrolyte solution.

A metal plating/deposition process is now becoming more and more popular in IC manufacturing. Besides copper interconnection in backend of line, in the field of advanced wafer level packaging, many technologies such as Cu pillar, RDL (redistribution layer), TSV and interposer also use the metal plating process. Due to high plating rate, electrochemical plating is mainly used for those processes mentioned above.
For a plating apparatus, especially for an electrochemical plating apparatus, an apparatus for holding a substrate is very important. A contact ring of the apparatus should be uniformly contact with a seed layer on a front side of the substrate. Meanwhile, the contact ring should not be contacted with electrolyte solution directly, so a seal ring is used for the isolation and the electrolyte solution doesn't get to the edge of the front side of the substrate. Otherwise, the edge of the front side of the substrate will be plated with metal, and the uniformity of the metal film deposited on the substrate will become worse.
U.S. Pat. No. 8,172,992 B2 discloses a clamshell used for the metal deposition process. A base plate of the clamshell, including a lipseal is made of a stiff, corrosive resistant material with a hydrophobic coating, such as polyamide-imide (PAI) and polytetrafluoroethylene (PTFE). But the thickness of the coating material is very limited, and normally the thickness is several microns. Therefore after long time use, during the frequent movement of the open and close the clamshell, the coating material will be damaged due to friction with the substrate and the seal effect becomes worse. The whole clamshell needs to be replaced with a new one. The life time of the clamshell is short. And the cost is very high by frequent replacing the clamshell. So new inventions are needed to reduce the cost for mass production.


The present invention is concerned with an edible, plastified dispersion containing less than 35 wt. % fat, which comprises from 10 to 35 wt. % continuous fat phase and from 90 to 65 wt. % dispersed aqueous phase, said dispersed aqueous phase having an average droplet size, indicated by the number weighted mean diameter, of less than 5.mu.m, which dispersion comprises less than 0.1 wt. % amino acid residues.

The present application is concerned with an edible, plastified dispersion containing less than 35 wt. % fat, which comprises from 10 to 35 wt. % continuous fat phase and from 90 to 65 wt. % dispersed aqueous phase.
Edible, plastified water-in-oil dispersions (often called spreads) that can be used as replacement for butter or margarine, having a fat content below 80 wt. %, are well known. A wide variety of such products is commercially available. Most of these products have a fat content of about 40 wt. %.
There is, however, need of spreads comprising a continuous fat phase and a dispersed aqueous phase having a fat content of substantially less than 40 wt. %.
A spread should have a plastified continuous fat phase to give it suitable spreadability and to prevent microbiological deterioration. It should not release moisture when it is being spread. Furthermore, a spread should be spreadable at refrigerator temperature, be stable at room temperature, but destabilize and release its flavour in the mouth. These goals are very difficult to achieve if only a small amount of fat is to be used to constitute the continuous phase.
In GB 2,035,360 a process is disclosed for the preparation of spreads containing 20 wt. % fat. According to this process, the aqueous phase is sprayed onto the fatty phase. During the addition of the sprayed aqueous phase, the emulsion is circulated through a static mixer to increase the viscosity. The final viscosity suitably is about 18000 mpa.s at a shear rate of 13 sec..sup.-1 and 2700 mpa.s at a shear rate of 134 sec..sup.-1 at 38.degree. C. When this viscosity has been obtained, the emulsion is cooled and worked to cause crystallization of fat to occur.
In practice, this process has not been successful. It is difficult to apply the process under factory conditions.
EP 0 011 344 teaches to incorporate in fat-continuous spreads containing 18-82 wt. % fat phase, a gelled aqueous phase having a softening point of at least 33.degree. C., showing a sharp decrease in gel strength at a temperature ranging from 45.degree. to 70.degree. C. and a gel strength at a temperature below the softening point ranging from 0.1 to 30 N/cm.sup.2. Spreads having very low fat contents, prepared with aqueous phase compositions as disclosed in EP 0 011 344 have been found to be unsatisfactory. In particular, such spreads tend to release water under spreading conditions.
U.S. Pat. No. 4,536,408 describes low-fat spreads comprising 15-35 wt. % fat and 15-35 wt. % of a non-gelling starch hydrolysate having a DE (dextrose equivalent) of 4-25. The products are prepared by cooling and mixing the fat into an aqueous solution of the starch hydrolysate with a high-speed blender until phase inversion occurs. The products disclosed in U.S. Pat. No. 4,536,408 have been found to have a poor oral response. They do not break down sufficiently in the mouth and, consequently, they have a poor flavour release.
The process employed to produce the spreads according to U.S. Pat. No. 4,536,408 involves phase inversion of an oil-in-water emulsion containing a fat blend having a melting point above about 38.degree. C., with a high-speed blender. Substantial problems would be encountered if one would try to carry out such a process, requiring the application of very high shear forces, on a factory scale.
Another disadvantage of the proposal of U.S. Pat. No. 4,536,408 is that it contains a very substantial amount of carbohydrate. Although the fat content of the product is low, the reduction in caloric value by reducing the fat content is partially offset by incorporating the starch hydrolysate.

Van Den Bergh Foods Co., Division of Conopco Inc.