In a hydrocracking unit, the flash gases from the high-pressure separator are fed to the bottom of an absorption zone where the entering gases are counter-currently contacted with a lean solvent. The lean solvent absorbs away the contained methane, ethane, propane, butanes and pentanes (C1+) from the contained hydrogen. The overhead gas stream from the absorption zone typically contains hydrogen at a purity of 90 to 98 mol %, or even higher, which is fed to the recycle gas stream to provide hydrogen purity in the range of 96 to 99 mol %, thereby providing an increase in the overall efficiency of the hydroprocessor unit. The process can also be employed with hydrotreating, hydrodesulfurization, hydrodenitrogenation and hydrodealkylation reactors.

This invention relates to improvements in hydroprocesses, such as hydrocracking and hydrotreating processes, used in refinery operations to produce middle distillates, including jet and diesel fuels.
In processes for the catalytic conversion of a hydrocarbon feed stock, the step of recycling a hydrogen-rich vapor or gas phase separated from the reaction zone effluent is common. Practical reasons for utilizing this step reside in maintaining both the activity and operational stability of the catalyst used in the process. In hydrogen producing processes, such as catalytic reforming, hydrogen in excess of that required for the recycle feed stream is recovered and utilized in other processes integrated into the overall refinery. For example, the excess hydrogen from a catalytic reforming unit is often employed as the makeup hydrogen in a hydrocracking process, where the reaction principally is hydrogen-consuming.
Regardless of the particular process, the recycled hydrogen is generally obtained by cooling the total reaction product effluent to a temperature in the range of from about 60xc2x0 F. (15.6xc2x0 C.) to about 140xc2x0 F. (60xc2x0 C.), and introducing the cooled effluent into a vapor-liquid separation zone. The recovered vapor phase required to satisfy the hydrogen requirement of the reaction zone is recycled and combined with the hydrocarbon feed stock upstream of the reaction zone.
The art has long recognized the importance of improving the purity of the hydrogen in the recycle stream of hydroprocessors, such as hydrocracking and hydrotreating units. Thus, it has been the goal of the art to provide enhanced efficiencies of hydrogen utilization with little additional energy consumption and without undue deleterious effects on the maintenance or operation of the hydrocracking equipment. It has also been recognized that by increasing the efficient use of hydrogen, existing equipment could be employed to increase the throughput of the feed stock and also increase the yield of C5 and higher hydrocarbons. A further obvious advantage to the more efficient utilization of hydrogen is the reduction in the amount of hydrogen that must be produced by, for example, a hydrogen plant to ensure that the hydroprocessing zone has sufficient hydrogen of adequate purity to enable the hydroprocessing to proceed in the most advantageous manner. See, for example U.S. Pat. No. 4,362,613 issued Dec. 7, 1982 to Monsanto Company.
In a conventional hydrocracking process, a heavy vacuum gas oil (VGO), which may be additionally mixed with demetalized oil (DMO) or coke-gas oil, is mixed with hydrogen gas to form a feed stream that is introduced under pressure into the top of a catalytic reactor. The VGO liquid and gaseous hydrogen mixture passes downwardly through one or more catalyst beds. The higher the partial pressure of hydrogen in the feedstream to the reactor, the greater will be the efficiency with which the heavier hydrocarbon feedstock is converted to the desired lighter middle distillate products, such as jet fuel and diesel fuel.
After passing through the catalyst, the hot reactor effluent is cooled and passed to a high pressure separator from which the liquid product stream is removed and, if desired, can be subjected to further fractionation.
The flash gases from the HP separator contain hydrogen and C1 to C5 hydrocarbons. These flash gases can contain for example from about 78 to up to 82 mole-percent (mol %) of hydrogen. In the conventional processes of the prior art, the flash gases are combined with a makeup hydrogen stream that is typically available at 96 to 99.99 mol % purity. The recycle gas and, if necessary, the makeup hydrogen streams are compressed and combined with the liquid feed stock at the inlet of the hydrocracking reactor. A portion of up to 2% of the flash gases from the high pressure separator are purged to the refinery fuel gas system to prevent the build-up of the light hydrocarbon products in the reactor gas recirculation loop.
If the heavy VGO feed is sour, i.e., it contains sulfur, the separated effluent gas stream will contain H2S in addition to the hydrogen and C1 to C5 hydrocarbons. In order to prevent build-up of H2S in the reactor gas recirculation loop, the flash gases are contacted with an amine solution to remove the H2S and to sweeten the gas stream. A portion of the sweetened low pressure flash gases are purged to the refinery fuel gas system to prevent build-up of C1 to C5 hydrocarbons in the reactor gas recirculation loop. The remaining sweetened recirculated gases are combined with makeup hydrogen, compressed and passed to the reactor inlet as part of the hydroprocessor feed. Depending upon the H2S content of the sour gas exiting the reactor, the hydrogen concentration of the sweetened recirculation gas stream can be increased to for example from 80 to 84 mol % hydrogen.
The type of feedstock to be processed, product quality requirements, and the amount of conversion for a specific catalyst cycle life determine the hydrogen partial pressure required for the operation of both types of hydroprocessing units, i.e., hydrocracker and hydrotreater units. The unit""s operating pressure and the recycle gas purity determine the hydrogen partial pressure of the hydroprocessing unit. Since there is limited control over the composition of the flashed gas from the downstream HP separator, the hydrogen composition of the recycle flash gas limits the hydrogen partial pressure ultimately delivered to the hydroprocessing reactor. A relatively lower hydrogen partial pressure in the recycle gas stream effectively lowers the partial pressure of the hydrogen gas input component to the reactor and thereby adversely affects the operating performance with respect to distillate quantity and quality, catalyst cycle life, heavier feed processing capability, conversion capability and coke formation. To offset the lower performance, the operating pressure of the hydroprocessing reactor has to be increased. Conversely, by increasing the efficiency of hydrogen gas recovery and hydrogen composition, the hydrogen partial pressure of the recycle gas stream improves thereby improving the overall performance of the hydroprocessing reactor as measured by these parameters.
In the practice of the prior art processes, there are only four ways known to improve the hydrogen partial pressure in the hydrocracker or hydrotreater unit. These are as follows:
1. increasing the hydrogen purity of the makeup stream from the hydrogen unit;
2. purging or venting gas from the high-pressure separator;
3. reducing the temperature at the high-pressure separator to decrease the entrainment of light hydrocarbons in the recycle gas, and
4. improving the hydrogen purity of recycle gas.
All of foregoing methods have a very limited capability for improving the performance of an existing unit. If the hydrogen plant optimizes the purity of the makeup hydrogen, it will be in the 96 to 99 mol % range. Since the high purity H2 makeup flow rate is typically only about one-third or less of the total combined hydrogen fed to the hydroprocessing reactor through recirculation of flashed recycle gas, the overall improvement in the H2 purity or concentration of the combined recycle and makeup gas streams is limited.
Purging or venting gases from the HP separator will result in the loss of some of the hydrogen in the circuit which must eventually be replaced, thereby putting a greater demand on the hydrogen production unit. The extent to which the separator temperature can be lowered is limited by nature of the process and this change has, in any event, a relatively minor effect on recycle gas H2 purity.
It has been recognized that unlike most hydrocarbon gases, hydrogen has the unique property of increasing its solubility in hydrocarbon liquids with increasing temperature. For example, the solubility of hydrogen in a particular oil at 900xc2x0 F. (482.2xc2x0 C.) can be five times as great as its solubility in the same oil at 100xc2x0 F. (37.8xc2x0 C.). This characteristic is utilized in a process disclosed in U.S. Pat. No. 3,444,072 to Lehman, where the loss of hydrogen dissolved in the liquid effluent from a high-pressure hydrogenation unit is minimized by separating the vapor effluent from the liquid effluent at approximately reaction temperature and pressure, and subsequently flashing the liquid effluent at substantially reaction temperature, but at a lower pressure. The gaseous effluent stream is cooled to ambient temperatures and then contacted in an absorber where it contacts absorber oil in counter-current flow. It is specifically stated that the absorber oil is not subsequently flashed because at ambient temperature the solubility of hydrogen in the absorber oil is not significant, as compared to the overall volumes of hydrogen in the operating system. The overhead absorber gas stream reportedly contains 70-80 volume % hydrogen, which is returned to the reactor in the recycle gas stream and combined with makeup hydrogen. The limited improvement offered by Lehman does not significantly change the hydrogen partial pressure.
Although a variety of processes have been proposed and adopted that are intended to improve the hydrogen utilization efficiency by increasing the purity of the hydrogen in the recycle gas stream, these processes typically result in significant additional equipment costs and/or require significant changes in operating conditions, such as temperature and pressure. The result of changes to the overall process cycle is increased capital and operating expenses.
One process that has been adopted to improve the hydrogen purity of the recycle stream is pressure swing adsorption (PSA). See, for example, U.S. Pat. No. 4,457,384 issued Jul. 3, 1984 to Lummus Crest, Inc. However, in order to incorporate the PSA process, the pressure of the reactor effluent gas stream must be reduced from 2,450 psig (172.2 kg/cm2g) to 350 psig (24.6 kg/cm2g). Although the purity of the recycle hydrogen can be increased to 99 mol %, the recycled gas must be subjected to compression to return it to 2,500 psig (175.8 kg/cm2g) before introduction into the hydroprocessor feed stream. The net result is that the capital, operating and maintenance costs are substantially increased by the addition of a large compressor that is required in the PSA process.
Prior art processes as described in U.S. Pat. No. 4,362,613 to MacLean have used membranes with pressure drops up to 150 atmospheres which incur substantial capital investment and operating costs.
It is therefore an object of this invention to provide an improved process for enhancing the efficiency of hydrogen utilization by means that are compatible with particular existing hydroprocessing units and that does not adversely affect the hydroprocessing throughput or the overall economies of the system, including capital expenditures and operating expenditures, the latter including maintenance and energy consumption.
As previously noted, the overall operating efficiency of the hydroprocessing reactor can be increased if the partial pressure of hydrogen gas in the feed to the reactor can be increased. It is therefore another object of the present invention to improve the operating performance of hydroprocessing units by increasing the through-put capacity of existing hydrocracking and hydrotreating reactors.
Another object of this invention is to improve the operating characteristics for hydrotreating and hydroprocessing in refinery units handling heavier oils.
A further object of this invention is to provide for the enhanced efficiency of hydrogen utilization in high pressure hydrogenation process while minimizing capital expenditures for additional equipment and their related operating expenses.
It is yet another object of this invention to enhance the quality and production rate of low-sulfur middle distillates, such as jet and diesel fuels, obtained from hydroprocessing units operated in accordance with the invention.
As used herein, the terms xe2x80x9chydrogen-richxe2x80x9d and xe2x80x9cC1+xe2x80x9d are intended to represent relative hydrogen and C1+ concentrations in a particular stream in comparison to the hydrogen and C1+ concentrations in other streams in the process of the present invention.
The terms xe2x80x9chydroprocessingxe2x80x9d and xe2x80x9chydroprocessorxe2x80x9d are to be understood to include hydroprocesses such as hydrotreating, hydrocracking, hydrodesulfurization, hydrodenitrogenation and hydrodealkylation reactors.
The improved process of this invention can be employed with hydrotreating, hydrocracking, hydrodesulfurization, hydrodenitrogenation and hydrodealkylation reactors. In the improved process for a hydrocracking unit, the flash gases from the high-pressure separator (HP Separator) are fed to the bottom of an absorption zone where the entering gases are counter-currently contacted with a lean solvent. The lean solvent absorbs away the contained methane, ethane, propane, butanes and pentanes (C1+) from the contained hydrogen. The overhead gas stream from the absorption zone typically contains hydrogen at a purity of 90 to 98 mol %, or even higher.
The partial pressure of hydrogen in the recycle gas stream is significantly improved with hydrogen purity in the range of 96 to 99 mol % by absorption of the hydrocarbon components (C1+) from the HP Separator flash gas stream. The increase in hydrogen partial pressure of the hydrogen gas input component to the hydrocracker results in an increase in the overall efficiency of the hydroprocessor unit.
The rich solvent from the absorption zone containing the C1+ components present in the HP Separator flash gas stream is flash regenerated to form lean solvent in accordance with U.S. Pat. Nos. 4,740,222; 4,832,718, 5,462,583, 5,546,764 and 5,551,972, the disclosures of which are herein incorporated by reference. The lean solvent, comprises predominantly the heavier C4 to C5 hydrocarbons and is returned to the top of the absorption zone (methane absorber).
It is known to the prior art from the description of the Mehra Process(copyright) disclosed in U.S. Pat. No. 5,551,972, and others, that the inventory of lean liquid solvent that is required to supply the feed to the absorption zone can be maintained and stabilized by controlling the temperatures at the exit of the liquid coolers. Thus, by monitoring solvent inventory, the volume of the liquid solvent stream lost due to equilibrium at the operating conditions within the absorption zone from lean solvent stream entering the absorption zone is made equal to the C4 to C5 components present in the HP Separator flash gas stream. By maintaining this balance, no makeup solvent is required to replenish the inventory once the process has reached steady-state operating conditions.
Some important advantages of utilizing the Mehra Process in the process of the present invention relate to savings in capital and operating costs. The liquid solvent is regenerated by flashing the absorption zone bottoms stream to reduce pressure in one or more flash drums connected in series, with no external heat added. After the initial batch of solvent charged to start up the process of the invention, no external solvent is required, since the absorption solvent consists predominantly of heavy components supplied by, or present in the hydrocarbon feed to the absorption zone.
Elimination of the need to introduce external solvent to the hydroprocessor system eliminates the possibility of contamination of the reactor feed and catalyst. It further reduces capital investment and operating costs since solvent storage, pumping and metering facilities are not required. The costs and equipment associated with buying, receiving, storing and charging makeup solvent are also eliminated. These advantages and cost savings are particularly significant for hydroprocessing units located in remote areas.
When the heavier liquid hydrocarbon feed to the hydrocracker contains sulfur compounds, the effluent H2S present in the flash gases from the HP Separator are also absorbed away along with the C1+ components from the H2 recycle gas stream and carried away in the rich solvent stream from the absorption zone. The absorbed gases present in the rich solvent from the absorption zone are separated in the solvent flash regeneration drums of the Mehra Process and contain H2S. Contained H2S in the separated sour C1+ components stream can be conveniently removed by amine treating in a significantly smaller treating unit. By comparison to known methods of the prior art, this invention requires a significantly smaller amine treating unit than would be required in the conventional process for treating the flash gas stream from the HP Separator. This is because the volume of gas containing the hydrogen sulfide has been greatly reduced by the prior separation and removal of the hydrogen component.
In accordance with the process of this invention, the hydrogen partial pressure of the recycle gas is increased. In a typical unit operation utilizing the process of this invention, the hydrogen concentration can be increased from about 84 mol % achieved in the prior art processes, to a value of from 90 to 99 mol %, or even higher. This improvement is equivalent to a 6 to 15 mol % increase in hydrogen purity. In units which operate at around 2,400 psig (168.7 kg/cm2g), for a 13 mol % increase in hydrogen purity, the increase in hydrogen partial pressure is around 312 psi (21.9 kg/cm2). This increase in the recycle gas purity attributable to the practice of the method of the present invention produces the following advantages in the unit""s operation:
1. higher product yields;
2. better distillate quality;
3. longer catalyst cycle life;
4. heavier feed processing capability;
5. higher conversion capability;
6. prevention of coke formation; and
7. improved feed distribution over catalyst bed.
The significance and effect of these advantages will be further discussed in the context of a hydrocracking unit.
11 Higher Product Yields
Operating at higher hydrogen partial pressures will result in lower start-of-run (SOR) temperatures, and a lower average bed temperature throughout the cycle. Doing so will increase the liquid product yield by about 4% and reduce lower-value gas make.
2. Better Distillate Quality
Higher hydrogen partial pressure improves the jet, diesel and unconverted oil quality. The estimated improvement in product quality by increasing the hydrogen partial pressure by 312 psi (21.9 kg/cm2) is estimated as follows:
a. Cetane Number improved by about 3 to 4; and
b. Aniline point improved by about 13xc2x0 F. (7.2xc2x0 C.) to 17xc2x0 F. (9.4xc2x0 C.).
3. Longer Catalyst Cycle Life
Higher hydrogen partial pressure results in an increase in the catalyst cycle life. The catalyst cycle life is determined for any given unit by the Start of Run (SOR) and the End of Run (EOR) temperature and the deactivation rate of the catalyst. SOR temperature is a function of the catalyst activity, unit pressure and the type of feed being processed. The catalyst cycle life is also a function of catalyst stability, which is measured in terms of deactivation rate (xc2x0 C. or xc2x0 F. per month). EOR temperature is determined by the reactor""s metallurgy or the unit""s economics (yield). Increasing the hydrogen partial pressure b)y 312 psi (21.9 kg/cm2) produces the following benefits:
a. Improved catalyst stability (relative deactivation rate) by about 70%. This is a major improvement for the catalyst cycle length. In a unit with 2 years cycle length, this improvement will increase cycle length to more than 3 years.
b. SOR temperature will be lowered by about 5xc2x0 C. to 6xc2x0 C. (9xc2x0 F. to 11xc2x0 F.), which is equivalent to about a 2 to 3 month increase in cycle length, depending upon the deactivation rate of the catalyst.
c. Catalyst Activity, measured in delta temperature required, will be improved by about 1xc2x0 C. (1.8xc2x0 F.) to 1.5xc2x0 C. (2.7xc2x0 F.) for every 10 psi (0.7 kg/cm2). Therefore, with a 312 psi (21.9 kg/cm2) increase in hydrogen partial pressure, the total improvement will be about 30xc2x0 C. (54xc2x0 F.) to 35xc2x0 C. (63xc2x0 F.) in average bed temperature.
All of these factors are related, but not cumulative, and the total increase in cycle life for a 2-year cycle length unit will be about one year in the cycle length for the unit. Thus a 50% increase in production is achieved.
4. Heavier Feed Processing Capability
Increasing the hydrogen partial pressure enables the unit to run more heavy feed. For example where the hydrocracker feed is limited to 15% DMO 85% VGO under prior art conditions, this percentage can be increased with the higher hydrogen partial pressure obtainable through the practice of the invention. While the particular catalyst employed will have an effect on the quantity of the increase, a minimum increase of about 5% in DMO processing capacity, i.e., 20% DMO 80% VG, can be expected.
5. Higher Conversion Capability
With the improved hydrogen partial pressure, the hydrocracker conversion can increase from 96% to 98%. Additionally, poly-nuclear aromatics (PNA) build-up will be reduced and consequently the drag stream will be less.
6. Prevention of Coke Formation
The tendency to form coke is substantially reduced with an increase in hydrogen partial pressure in the reactor. Availability of more hydrogen reduces the hydrocarbon condensation in catalyst pores and subsequent plugging of the active sites on the catalyst.
7. Improved Feed Distribution Over Catalyst Bed
With higher hydrogen partial pressure feed distribution is substantially improved due to lower molecular size of gases which, in turn significantly reduces flow maldistribution and formation of hot spots in the reactor.
As will be apparent to one of ordinary skill in the art from the above analysis, the financial benefits associated with the practice of the invention are also significant. For example, a typical hydrocracker with a rated capacity at 30,000 BPD can achieve an improvement in total annual revenues from the incorporation of over $17 MM/yr in current dollars by adopting the process of this invention.

Process for increasing hydrogen partial pressure in hydroprocessing processes


A composition includes a liposome which has a polynucleic acid and a peptide capable of disrupting membranes under acidic conditions encapsulated within it. The composition is used for efficient transfer of nucleic acids into cells both in vitro as well as in vivo.

The development of gene therapy for inherited or acquired diseases is dependent on the establishment of safe and efficient gene delivery systems. One method for in vivo gene transfer uses viruses to transfer the exogenous gene into cells, but this method also transfers viral genes into the cells which may produce undesirable effects. In addition, contamination by wild type viruses is also a risk in this method.
Another method for in vivo gene transfer uses a complex of positively charged liposomes (composed of synthetic lipids) that bind to the DNA (the DNA is not encapsulated in the liposomes) (Zhu, N., et al., Science, 261:209-211, 1993). However, the toxicity of positively charged liposomes (Raz, E., et al., In: Vaccines, Cold Spring Harbor Laboratory Press. Cold Spring Harbor, N.Y., 1994) limits the use of this method.
A complex of poly-L-lysine coupled to DNA and a ligand which can be targeted to the cell surface was also used for in vivo gene transfer (Wu, G. Y. and Wu, C. H., J. Biol. Chem., 263:14621-14624, 1988; Perales, J. C., et al., Proc. Natl. Acad. Sci., USA 91:4086-4090, 1994). However, transient expression of the transferred gene and immunogenicity of the complex limits the use of this method. Neutral or negatively charged liposomes (composed of synthetic or natural lipids) that encapsulate DNA were hitherto used for in vivo gene transfer (Nicolau, C., et al., Proc. Natl. Acad. Sci., USA, 80:1060-1072, 1983; Liebiger, B., et al., Biochem. Biophys. Res. Commun., 174:1223-1231, 1991).
Such liposomes are non-toxic, non-immunogenic and biode-gradable (Storm et al. In: Gregoriadis, G. (Ed), Liposome Technology, 2nd Ed. CRC Press, Baca Rator, Fla. 1993, 00.345-383) and are therefore good candidates for repetitive high dose treatment. However, the gene transfer efficiency in these experiments was low. One possible explanation for the low efficiency is that the DNA, which is encapsulated in liposomes and enters the cytoplasm through the lysosome (Cudd, A., and Nicolau, C., Biochim. Biophys. Acta, 845:477-491, 1985), is degraded by active DNases in the lysosome.
Therefore, treatments that inhibit lysosome activities can increase the amount of liposome-encapsulated DNA inside the cells.
Indeed, adenovirus particle and peptides derived from the N-terminal of the Influenza virus hemagglutinin subunit HA-2, which can disrupt membrane at low pH and therefore disrupt the lysosome membrane, were shown to enhance in vitro gene transfer efficiency when coupled to poly-L-lysine and DNA (Curiel, D. T., et al., Proc. Natl. Acad. Sci., USA, 88:8850-8854, 1993: Wagner, E., et al., Proc. Natl. Acad. Sci., USA, 89:7934-7938, 1992).
The efficiency of cationic-liposome mediated in vitro DNA transfection into cells was also shown to be increased when the cationic-liposomes were mixed with the DNA to be transfected together with two additional peptides derived from the Influenza virus hemagglutinin protein to form a complex between these three components (Kamata, H. et al. Nuclear Acid Research 22:536-537, 1994).
Fusion of liposomes prepared by reverse-phase evaporation (RPE) carrying DNA or protein molecules to target cells was shown to be mediated by Sendai virus proteins (Kameda, Y. et al, Exp. Cell Res. 173:56, 1987) or influenza virus proteins (Lapidot, M., Loyter, A., Exp. Cell Res. 189:241-246, 1990; Tikchonenko, T. I. et al, Gene 63:321-330, 1988) which were introduced into the liposome membrane (i,e, were present on the liposome's outer surface). The introduction of the DNA or protein encapsulated in the liposome was dependent on the presence of an active viral fusion protein and, therefore, either intact Sendai or influenza virus particles or their reconstituted envelopes were required. Liposomes containing modified reconstituted viral envelopes integrated in their lipid bilayer (Gould-Fogerite, S. et al, Gene, 84, 429-438, 1989) were also prepared by the protein-cochleate technique. Such liposomes were used for stable gene transfer and expression in animals.
All the above mentioned liposomes have large viral particles or reconstituted viral envelopes integrated in their lipid membrane which protrude outwards from the liposome membrane. In vivo administration of liposomes carrying such large viral particles may be hindered by the high antigenicity of such large particles as well as occasionally by their toxic effects.


There are disclosed a device and method for saving power supply of a steering sensor for a vehicle having a conventional circuit for detecting a steering angle and a supplementary circuit for detecting an amount of steering angle change when an ignition switch is turned off. The conventional circuit comprises a rotary encoder for generating two signals of sine waveform-like having a phase discrepancy of 90 degrees responsive to a rotation of a steering shaft, and a microcomputer for calculating an absolute angle from the sine waveform-like signals. The supplementary circuit comprises a waveform shaping circuit for converting the sine signals into two rectangular wave pulse signals. While the switch is turned on, the circuit continues to detect the absolute angle based on the sine waves. When the switch is turned off, the supplementary circuit counts and hold the change amount of the angle as the pulse signals while the circuit maintains the storage of the last absolute angle. The microcomputer reads numbers of the pulse signals to set the initial absolute angle and to start operation for detecting the absolute angle.

The present invention relates to a device and a method of decreasing electric power consumption in a steering angle detecting system for a vehicle, and more particularly, relates to the system with an analog-type steering sensor which detects a steering angle and direction of the vehicle by an output voltage having a sine wave form.
Generally, the vehicle performing various controls such as anti-lock control responsive to a steering angle of a steering wheel requires a steering sensor for detecting rotational angle and direction of a steering shaft. The steering sensor is attached to a steering system 1 comprising a steering gear box 2 which is connected to knuckle arms 3 at both ends thereof through tie-rod ends 4, respectively, and a steering column 5, as shown in FIG. 1A. The column 5 is a hollow circular cylinder through which a steering shaft 50 is inserted, as shown in FIG. 1B. The steering shaft 50 is connected to the box 2 at one end thereof through a universal joint 6. The other end of the column 5 is connected to a steering wheel 7 through a column cover 8. The cover 8 is fixed to the vehicle body by a bracket 9 and fastening bolts (not shown).
The shaft 50 has a large diameter portion 51 connected with the wheel 7, a small diameter portion 52 connected with the joint 6, a middle diameter portion 53 located between both portions 51 and 52 for connecting them to each other. The steering sensor 10 comprises photo-interrupters 11 and 12 respectively located in positions 90 degrees apart from each other, a photo-interrupter 13 for detecting a neutral position of the steering wheel 7, and a steering disc 55 fixed on an outer surface of the middle diameter portion 53 of the shaft 50, as shown in FIG. 1B,. The photo-interrupters 11 to 13 include photo emitters 11a to 13a such as light emitting diodes, and photo receptors 11b to 13b each paired with the emitters 11a to 13a, respectively. The disc 55 is located between the emitters 11a to 13a and receptors 11b to 13b, and has a plurality of slits 56 formed radially and opposed to the emitters 11a and 12a and the receptors 11b and 12b at even radius intervals, so that each of the receptors 11b and 12b generates the sine wave voltage at one pitch of the slit. The disc 55 also has a neutral slit 57 opposed to the emitter 13a and receptor 13b for indicating the neutral position of the shaft 50. Accordingly, the disc 55 is a so-called encoded disc.
The aforementioned prior art uses an optical type rotary encoder having the encoded disc, the emitter and the receptor as the steering sensor. Another example of the prior art may use a magnetic type rotary encoder as the steering sensor 10. The magnetic type encoder has a steering disc or drum mounted on the steering shaft 50 on which N poles and S poles alternate at even intervals. The magnetic encoder has magnetic reluctance elements or Hall effect elements, which generate a voltage of sine waveform-like dependent on the rotation of the disc or drum. An example of the prior art is disclosed in Japanese Utility Model Laid-open No. 62-51214 (1987).
There are various problems when the aforementioned rotary encoder such as the optical type or the magnetic type is applied to the steering sensor for the vehicle.
First, as the above rotary encoder basically detects an amount of a relative rotational angle change of the steering shaft, it is necessary for detecting an absolute steering angle to set a zero angle as the neutral position and to calculate and store a change amount from the neutral position by a microcomputer. Accordingly, a neutral position mark is formed on the rotational disc 55 or the rotational drum, so that the neutral position is set.
However, as the steering shaft generally enables to rotate two to four rotations between full rightward and leftward steering operations, the neutral position mark is detected at least three times at a zero degree point (neutral point), and two points when the steering shaft is turned 360 degrees from the zero degree point in the right and left directions. Accordingly, though the sensor may continue to detect the absolute angle as described above while the power is in "ON" state once the stored absolute angle is lost by shutting the power of the microcomputer, it is impossible to detect the absolute angle thereafter. Even if the power is supplied to the microcomputer again after once shutting, the zero degree neutral point needs to be reset from three detection points of the neutral position mark by complicated operation.
Accordingly, the power continues supply to at least a memory storing the absolute angle even if the ignition switch is turned off at parking, so that the absolute angle is kept stored and the change of the steering angle at parking may be detected.
A second problem relates to the high resolution at a steering angle detection.
For example, in the optical type rotary encoder, the receptor 11b of the photo-interrupter receives one time of the change of the light and shade and converts it into output voltage having the sine wave form while the rotary disc rotates by one pitch of the slits. In the magnetic rotary encoder, the magnetic sensor detects one time of the change of the magnetic force and converts it into the output voltage of the sine wave form while the rotary drum rotates by one pitch of the N and S poles.
Then, the rotary disc or drum rotates by one pitch and generates an output signal of one wave form. The output signal is changed into pulse forms which are counted by the microcomputer to obtain the change amount of the steering angle by the usual detection method for the steering angle. Accordingly, the resolution of the steering angle detection is determined by the number of slits in the rotary disc or the number of magnetic poles of the rotary drum in the method.
However, the rotary disc or drum may not be made larger due to space restrictions, so that it is impossible to increase the slits or magnetic poles. Accordingly, it is impossible to make a resolution higher enough.
In order to solve the problem, there has been developed a steering angle detection method using an optical or magnetic rotary encoder for generating two analog signals which vary like sine wave with a phase discrepancy of 90 degrees to each other as the vibration of the steering angle. A microcomputer calculates a steering angle on the basis of two digital signals converted from the analog signals by an analog/digital converter. By the method, it is possible to make the resolution higher in spite of the number of slits or magnetic poles because of one-to-one correspondence between the analog signals and the steering angle.
However, as a plurality of cycles of the sine wave are output in a rotation range of the steering shaft, the above method has the problem that the absolute angle is not able to be detected if the reference position is not reset once the power source is shut off in the same manner as the pulse count type.
As described above, the method for directly calculating the steering angle from two sine wave signals by analog/digital converter, is effective as the steering angle detection method for the vehicle because of the increased resolution. However, the method makes the power consumption of the steering angle detection system large in comparison with the pulse count method, so that it is difficult to compensate for extended operation by a backup of the battery at the parking.

Device and method for decreasing power consumption of a steering angle detecting system for vehicle


A peripheral processing device comprises a physical interface for connecting the processing device to a host computing device through a communications protocol. A local controller connected to local memory across an internal bus provides input/output access to data stored on the processing device to the host through a file system API. A neural processor comprises at least one network processing engine for processing a layer of a neural network according to a network configuration. A memory at least temporarily stores network configuration information, input image information, intermediate image information and output information produced by each network processing engine. The local controller is arranged to receive network configuration information through a file system API write command, to receive input image information through a file system API write command; and to write output information to the local memory for retrieval by the host through a file system API read command.

Referring to FIG. 1, convolutional neural networks (CNNs) 10 usually comprise multiple layers including convolutional layers 21-1, 12-2 or fully connected layers 14-1, 14-2, typically accompanied by pooling 16-1, 16-2, 16-3 or regularization tasks:
A Convolutional Layer convolves, for example, an input image or map "I" (in general nD) with a kernel "W" (in general n+1D) and adds a bias term "b" (in general nD) to it. The output is given by:P=I*W+b where * operator is (n+1)D convolution in general. Typically, n=3, but for time series applications, n could be 4. The convolution output P is then typically passed through an activation function. During training, the kernel and bias parameters are selected to optimize an error function of the network output. Convolution layers are used to create feature maps that, later in the processing chain, are interpreted by fully connected layers. Typically, multiple convolution layers are employed to generate in turn multiple feature maps.
A Fully Connected Layer is similar to classical Neural Network (NN) layers where all the neurons in a layer are connected to all the neurons in their subsequent layer. The neurons give the summation of their input multiplied by their weights and this is then passed through their activation functions.
In the example of FIG. 1, the last fully connected layer 14-2 comprises 3 output neurons, each providing a value for each category of object the network is attempting to identify in an input image (or image window).
Note that fully connected layers can be regarded as a form of convolution layer where the kernel size (width×height×channels) is equal to the size of the (multi-channel) map to which it is applied and for the purposes of simplicity, the term CNN is employed when implementing such layers.
A Pooling Layer applies a (usually) non-linear transform (Note that "average pooling" is a linear transform, but the more popular "max-pooling" operation is non-linear) on an input image to reduce the size of the data representation after a previous operation. It is common to put a pooling layer between two consecutive convolutional layers. Reducing the spatial size leads to less computational load and also prevents over-fitting as well as adding a certain amount of translation invariance to a problem. These layers are particularly important to reduce the complexity of parameters, computation and size of intermediate layers that need to be saved in a temporary memory between layers.
Regularization (not illustrated in FIG. 1) prevents overfitting inside a network. One can train a more complex network (using more parameters) with regularization and prevent over-fitting while the same network would get over-fitted without regularization. Different kinds of regularizations have been proposed including: weight regularization, drop-out technique and batch normalization. Each of them has their own advantages and drawbacks which make each one more suitable for specific applications.
As convolution layers require a lot of multiply-accumulate type of instructions, running CNNs on general purpose processing architectures (e.g. CPU/DSP) requires a large amount of processing power.
In order for modern application processors to support CNNs, there would be a need to: upgrade the memory subsystem (to provide much larger bandwidth); allow for larger power consumption (as a consequence); and upgrade processing power (TFLOPs processing power to run a decent real-time network).
To run the lightest typical object detector network architecture, a given system would need to have roughly one extra LPDDR4 (low power double data rate) 32 bit channel and an upgraded application processor capable to run anywhere from 100 GMACs (equivalent of several quad core ARM Cortex A75) to several TMACs (several tens of ARM Cortex A75 cores).
Referring to FIG. 2, PCT Publication No. WO 2017/129325 (Ref: FN-481-PCT) discloses a programmable CNN (PCNN) engine 30′ providing a general purpose neural processor, capable of loading its networks (e.g. equivalent of the program in a traditional CPU) through a separate memory channel 38 from the input image data 36 and results 39. The PCNN is an iterative processor that executes the networks layer by layer. The configuration of the layers, whether specifically convolutional, fully-connected, pooling or un-pooling, the weights types and values and the neuron's activation functions are all programmable via the network definition.
Use of such a processor 30′ in conjunction with a separate host processor 50 can reduce the power requirements for a system while enabling the network to operate in real-time on streams of images. However, the engine 30′ needs to be integrated within a system at manufacture.
Separately, it has been proposed to move all the logic and temporary memory required by a CNN to a high speed peripheral and build a co-processor with dedicated CNN accelerators and very large local memory bandwidth, for example, the Deep Learning Inference Accelerator (DLIA) from Intel Corporation; or the neural network accelerator on a USB stick provided by Movidius. However, these solutions require host kernel drivers and so are not readily deployed with existing systems.


A table includes a main support platform having an upper surface; opposite side walls fixedly mounted on the main support platform at opposite sides thereof; a rear wall fixedly mounted on the main support platform at a rear edge thereof, with the opposite side walls and the rear wall extending to a height above the upper surface of the main support platform; a support extension platform for effectively forming an extension of the upper surface of the main support platform; opposite side walls fixedly mounted on the support extension platform; and pivot pins for pivotally connecting pivoted ends of the opposite side walls which are mounted on the support extension platform to the opposite side walls mounted on the main support platform, such that the support extension platform can be pivoted between a position in which it effectively forms an extension of the main support platform and a position in which it extends above the opposite side walls and the rear wall which are mounted on the main support platform, in spaced relation thereto.

The present invention relates generally to tables, and more particularly, is directed to a table that can safely be used as a changing table for infants.
The use of infant changing tables as articles of furniture has become widespread. Changing tables, in addition to serving as supports for infants when changing soiled diapers, also generally include drawers, shelving or the like for storage of infant's clothing, diapers, changing materials, and the like. As a result, changing tables are often independent, self-supporting articles of furniture.
In many instances, the changing table will be incorporated with some other item of furniture. For example, the changing table may be secured to the end panel of a crib. This provides ease of use of the changing table, while reducing the amount of floor space that is required.
In order to further conserve floor space, many changing tables provide a pivoting support extension. Specifically, the changing table includes a main upper support platform, with two opposite side walls and a rear wall in surrounding relation thereto. This prevents the infant from falling off of the changing table. However, there is no front wall, in order to provide access to the infant by an adult.
The pivoting support extension includes an extension platform pivotally mounted to the front edge of the main upper support platform or to the front ends of the side walls. Thus, the extension platform can be pivoted between an open position adjacent to and coplanar with the main upper support platform and a closed position parallel to and spaced above the main upper support platform. In the open position, the extension platform functions as an extension of the main upper support platform for supporting the infant. In the closed position, the extension platform is out of the way so as to effectively reduce the amount of floor space.
However, in the latter closed position, the extension platform rests on the upper edges of the side walls and the rear wall. With such an arrangement, there is the possibility that an infant's fingers can get caught between the rear and/or side walls and the extension platform when the extension platform is in the closed position. This is particularly the case where the changing table is attached to an end panel of a crib. In such case, an infant standing in the crib can reach over and slightly raise the extension platform. When the infant releases the extension platform, it can crush his fingers between the extension platform and the rear and/or side walls of the changing table.
The above problem is not limited to infant changing tables. For example, in the workplace, various heavy metal working tables and the like are provided with similar arrangements. In such case, a worker can get his fingers caught in the same manner as described above.

Table having a pivoting support extension


An electrode material for lithium secondary battery comprises a nanoheterostructure which contains a lithium-ion conductor and an electrode active substance of which one inorganic component is a matrix, and of which the other inorganic component is three-dimensionally and periodically arranged in the matrix, and has a three-dimensional periodic structure whose average value of one unit length of a repeated structure is 1 nm to 100 nm.

1. Field of the Invention
The present invention relates to an electrode material for lithium secondary battery having a nanoheterostructure, a method for producing the same, and a lithium secondary battery including the same.
2. Related Background Art
Lithium secondary batteries have been known as secondary batteries with high energy density, and have conventionally been used as power sources for various electronic instruments. However, conventional lithium secondary batteries do not necessarily have sufficient output characteristics, for example, sufficient discharge capacity. Hence, a lithium secondary battery with higher output characteristics has been desired.
M. Hara et al. discloses, in J. Power Sources, 2009, vol. 189, pp. 485 to 489, a lithium secondary battery comprising, as a positive electrode, a composite material obtained by forming a lithium-ion conductor (Li0.35La0.55TiO3 (LLT)) having an inverse opal structure by a sol-gel method using monodispersed polystyrene beads as a template, and filling the pores of this porous LLT with an electrode material (LiMn2O4) by a sol-gel method.

This patent is subject to a terminal disclaimer.

Electrode material for lithium secondary battery, method for producing the same, and lithium secondary battery including the same


A viable T-gate FET is produced even when the cap of the "T" is mis-aligned from the stem of the "T". A subtractive etch is used to selectively etch the material forming the cap of the T-gate and the material forming the stem of the T-gate in order to avoid the etching away of portions of the stem if the cap is mis-aligned relative to the stem. To that end, germanium (Ge) may be used as the material for the cap of the T-gate and poly silicon (polySi) may be used as the material for the stem of the T-gate. Since germanium can be etched selectively relative to silicon from 10:1 to as much as 20:1, the cap of the T can be formed without appreciable damage to the stem portion and thus without damage to the resultant FET device.

1. Field of the Invention
The present invention generally relates to a method of manufacturing a T-gate field effect transistor (FET) and, more particularly, to a method of manufacturing a viable T-gate FET even when the cap of the "T" is mis-aligned from the stem of the "T".
2. Description of the Related Art
In conventional FET processing the limits of the poly gate length and the channel length are dependent on the lithography resolution. The self-aligned, or symmetrical, T-gate transistor allows for a lithography-independent sub 0.1 .mu.m channel and a longer gate while optimizing resistance and capacitance characteristics.
Self-aligned FETs are widely used in high speed integrated circuits to minimize the gate-source and gate-drain parasitic capacitance. Most self-aligning processes use a refractory metal as a mask for self aligning implantation of the n+ (or p+) source and drain regions. In these processes, it is important to control the distance between the gate conductor and the n+ source and drain implant regions since these parameters effect the speed and performance of the FET.
Control of n+ source and drain implants to the gate metal may be accomplished by using a T-shaped gate. Conventionally, this requires the deposition of another layer, either a dielectric or metal, on top of a refractory metal and acts as the mask for subsequent etching and undercutting of the underlying refractory gate. The etching process is done either by wet chemical etch or dry etching. The sacrificial top layer is then removed prior to high temperature annealing of the n+ source and drain implants due to lack of high temperature stability of the top layer. Removing the top layer eliminates the choice of fabricating the ohmic metal contacts in a self-aligned manner with respect to the gate metal.
U.S. Pat. No. 5,550,065 to Hashemi et al. discloses a method for fabricating a self-aligned FET on a surface of a semiconductor substrate using LaB /TiWN as a T-shape gate structure formed by a controllable dry etching of the TiWN using LaB.sub.6 as the mask which allows control of n+ implant distance to gate edge. The high temperature stability of the LaB.sub.6 /TiWN structure allows the "T-shaped" gate to be preserved during the high temperature post n+ source and drain implant annealing step and subsequently to be used for the self-aligned formation of source and drain ohmic contact metals on the surface of the substrate and in spaced relationship while simultaneously depositing extra low resistance metal over the "T-shaped" gate metal, producing low gate resistance.
The process for manufacturing T-shaped gates requires high tolerances between the cap (horizontal top) of the "T" and the stem (the vertical portion) of the "T". When forming the cap of the T with a subtractive etch process, if there is any mis-alignment between the cap and the stem, some of the stem of the T will be accidentally but unavoidably etched away leading to device failure.
U.S. Pat. No. 4,965,218 to Geissberger et al. discloses a self aligned T-gate FET which allows for misalignment between the cap of the T and the stem of the T while still producing a viable device. In particular, windows are patterned in an encapsulant layer over the gate area. A non-critically aligned photoresist mask over the encapsulant layer is used to expose substantially the entire top surface of the stem of the T-gate. Gold is subsequently evaporated onto the photoresist and gate stem and lifted off with the photoresist to produce a non-critically aligned (+/-0.5 micron) cap of the T-gate which is firmly bonded to the stem. The technique allows for gross misalignment between the cap and the stem of the T-gate metallization without increasing the FET gate length. Hence, the stem and the cap can be substantially mis-aligned with respect to one another and still produce a viable operating device. However, this method relies on an encapsulant layer to protect the stem portion of the T-gate as the cap is formed and further is expensive owing to the use of gold as the material for the cap.

Method for manufacturing a field effect transitor (FET) having mis-aligned-gate structure

International Business Machines Corporation


Methods and apparatuses for matching impedances in a flip-chip circuit assembly are presented. An apparatus for matching impedances in a flip-chip circuit assembly may include a first circuit associated with a first die and a through silicon via (TSV) coupling the first circuit to a second circuit. The apparatus may further include a first impedance matching inductor interposed between the TSV and the second circuit. A method for matching impedances in a flip-chip circuit assembly may include providing a die having a first circuit, and forming a TSV over the die. The method may further include providing a second circuit and forming a first impedance matching inductor interposed between the TSV and second circuit.

Die stacking may be used in three-dimensional flip-chip integration, and typically involves mounting one or more chips on another chip in a single semiconductor package. This process can increase the amount of circuitry that can be housed within a package of a given size, and thus can reduce the area utilized on a printed circuit board. Die stacking may also simplify the assembly of printed circuit boards since multiple dies may be attached to a printed circuit board in a single operation. Die stacking also has the potential to improve the electrical performance of devices in which it is used since the interconnections between elements on each of the stacked dies may be shorter than the interconnections that would be required to connect the die elements on a planar surface. This can result in faster signal propagation and may also reduce cross-talk.
Connections may be formed between circuits residing on stacked dies by using Through Silicon Vias (TSV's). As the name suggest, a TSV is a conductive via formed through a layer of silicon that provides electrical connections between circuits on both sides of the via. A conventional die stacking arrangement using TSV's is illustrated in FIG. 1. Here, a first die 100 is connected to a second die 112 using a TSV 106 and a microbump 110. The first die 100 may include a substrate 102 on which conventional layers of circuitry are formed and an outer metal layer 104. The through silicon via 106 may be formed in the substrate 102 by conventional processes, which can involve thinning the substrate to expose an end of the TSV 106, and a redistribution layer 108 may be added to the side of the substrate opposite the conventional layers of circuitry. The microbump 110 may be formed on the redistribution layer 108 to provide a mechanical/electrical connection to the TSV 106. A second die 112 that can be stacked on the first die 100 may include a substrate 114, an outer metal layer 116, and a microbump 118. Electrical connections are formed between the first die 100 and the second die 112 by inverting the second die 112 and connecting the microbump 118 on the second die 112 with the microbump 110 on the first die 100.
The TSV and the microbumps may form a connection set having two ports (not shown) which carry the signal bi-directionally between the circuits on the two dies 100 and 112. This arrangement may provide a satisfactory connection between stacked dies for signals having lower frequencies. However, at higher frequencies, such as, for example, RF frequencies over GHz, the connection set may introduce a parasitic reactance into the signal path. This parasitic reactance may be capacitive, and can adversely affect the performance of the circuitry associated with die 100 and/or die 112.
Accordingly, there is a need for improved coupling techniques used in three dimensional flip chip assemblies, which do not introduce parasitic impedances that may affect the performance of integrated circuits.

Apparatus and method for through silicon via impedance matching


A transmitting apparatus is used in an electrical frequency division multiplex transmission system including nodes that are on an optical transmission path and that respectively frequency-multiplex a sub-carrier of a unique frequency and a carrier wave to transmit information to a receiving apparatus on the optical transmission path. The transmitting apparatus is disposed in each node and includes a determining unit that receives an input of information concerning unused sub-carriers of a transmission signal in the optical transmission path and determines transmission of the information to the receiving apparatus using an unused sub-carrier; an electrical frequency division multiplex transmission unit that using a frequency of the unused sub-carrier determined by the determining unit, modulates the input information to be transmitted to the receiving apparatus; and a coupling unit that adds to the transmission signal in the optical transmission path, a modulated modulation signal.

Wavelength division multiplexing (WDM) is a technique of multiplexing optical signals of wavelengths (optical carrier frequencies) that differ from one another. According to WDM, baseband modulation is executed for each carrier wave among carrier waves of differing wavelengths and an optical coupling and decoupling device executes multiplexing and de-multiplexing of the carrier waves. To multiplex at narrow wavelength (frequency) intervals, highly precise wavelength control is required of the transmitters and wavelength de-multiplexer. Consequently, multiplexing at narrow wavelength (frequency) intervals is difficult.
Optical frequency division multiplexing (FDM) may be performed. In a system employing optical FDM, along an optical transmission path such as an optical fiber, plural nodes are disposed and carrier light is transmitted from a light source of a transmitting apparatus disposed at the starting point of the optical transmission path. Data signals at different sub-carrier frequencies are multiplexed and transmitted with the carrier wave from the plural nodes. The receiving side (a receiving apparatus) disposed at the end point of the optical transmission path receives information transmitted from the nodes (see, e.g., Japanese Laid-Open Patent Publication No. 2011-215603).
In the system employing optical FDM, the data signals are multiplexed with carrier light in a single optical transmission path and therefore, the receiving side merely has to receive the carrier light and therefore, can receive the information transmitted by the plural nodes by a simple configuration compared to that of the WDM.
However, the efficiency of frequency use cannot be improved for a system employing the conventional optical FDM. The sequence in which signals are transmitted by each node in the optical FDM system varies. Consequently, unused frequency bands occur for the frequencies (the sub-carriers) of the unused nodes in the entire frequency band used by the optical FDM.
In a case where the unused frequency bands are discrete, if frequency multiplexing is to be executed using a modulation signal corresponding to a single carrier, the configuration becomes complicated. Plural mixers and frequency oscillating devices are necessary to determine the frequency position (frequency difference) of the coupled signal against that of the carrier wave (at the frequency ν0). Therefore, the configuration becomes complicated and the cost increases.

Transmitting apparatus, receiving apparatus, optical frequency division multiplex transmission system, and optical signal communication method


A method includes positioning a robot in a plurality of postures in a substrate processing system relative to a fixed location in the substrate processing system and generating sensor data identifying a fixed location relative to the robot in the plurality of postures. The method further includes determining, based on the sensor data, a plurality of error values corresponding to one or more components of the substrate processing system and causing, based on the plurality of error values, performance of one or more corrective actions associated with the one or more components of the substrate processing system.

Electronic device manufacturing systems, such as substrate processing systems, include multiple process chambers and load lock chambers. Such chambers are included in cluster tools where a plurality of process chambers are distributed about a transfer chamber, for example. Electronic device manufacturing systems also include a factory interface and storage areas (e.g., front opening unified pods (FOUPs)). Electronic device manufacturing systems employ articulated robots or multi-arm robots, which are housed within the transfer chamber to transport substrates between the various process chambers and load lock chambers and are housed within the factory interface to transport substrates between the storage areas and the load lock chambers. For example, the robots transport substrates from chamber to chamber, from load lock chambers to process chambers, from process chambers to load lock chambers, from load lock chambers to storage areas, and/or from storage areas to load lock chambers. Efficient and precise transport of substrates between the various portions of the electronic device manufacturing system improves system throughput, thus lowering overall operating costs.
In many single blade (e.g., end effector) and dual blade robots, a wrist to which each of the single or dual blades are attached is capable of independent rotation, referred to as yaw rotation. In some examples, each robot employs three arms (upper arm, forearm, and wrist) driven by one or more motors. In some examples, each robot also employs four arms (upper arm, forearm, additional arm, and wrist) driven by one or more motors. In each of these robots, the wrist is capable of independent yaw rotation. A blade is coupled to a wrist and is used to carry content (e.g., a substrate) to or pick content (e.g., a substrate) from a destination such as a process chamber or a load lock chamber.

Apparatus, systems, and methods for improved joint coordinate teaching accuracy of robots


A folded monopole antenna that supports lower and upper frequency bands may be used in CDMA, WLAN, or other wireless communications systems. The folded monopole antenna may be located in a handset next to a vertical ground plane. The folded monopole antenna may be folded at least twice and connected to the ground plane through a reactance. The dimensions of different sections of the folded monopole antenna define lower and upper frequency band characteristics, and an offset location of an input feed affects the bandwidth of the frequency bands. The reactance between the antenna and ground plane can be selected to fine tune the frequency bands. Various input feeds, including a co-planar waveguide, may be employed. Dynamically adjustable reactances may be used in the input feed and ground line for adapting the antenna to various environments.

Code division multiple access (CDMA) communications systems, such as the communications system 100 of FIG. 1, provide wireless communications between a base station 110 and one or more mobile or portable subscriber units, such as a cell phone 130, Personal Digital Assistant (PDA) 140, or Portable Computer (PC) 135 with cellular modem. The base station is typically a computer-controlled set of transceivers that are interconnected to a land-based Public Switched Telephone Network (PSTN) 112 that is connected to a Wide Area Network (WAN) 115, such as the Internet, via a gateway (not shown).
The base station further includes an antenna apparatus 105 for sending forward link radio frequency signals 150a to the mobile subscriber units and for receiving reverse link radio frequency signals 150b transmitted from each mobile subscriber unit. Each mobile subscriber unit also contains an antenna apparatus for the reception of the forward link signals and for the transmission of the reverse link signals. Similar communications techniques are found in Wireless Local Area Networks (WLAN's) 117, where a network router 120 connects wireless access points 125 to the WAN 115. In either the CDMA or WLAN system, multiple mobile subscriber units may transmit and receive signals on the same center frequency, but unique modulation codes distinguish the signals sent to or received from individual subscriber units.
In addition to CDMA, other wireless access techniques employed for communications between a base station and one or more portable or mobile units include those described by the Institute of Electrical and Electronics Engineering (IEEE) 802.11 standard, optionally used in the WLAN 117, and the industry-developed wireless Bluetooth standard. All such wireless communications techniques require the use of an antenna at both the receiving and transmitting site. It is well-known by experts in the field that increasing the antenna gain in any wireless communications system has beneficial effects.
A common antenna for transmitting and receiving signals at a mobile subscriber unit is a monopole antenna (or any other antenna with an omni-directional radiation pattern). A monopole antenna consists of a single wire or antenna element that is coupled to a transceiver within the subscriber unit. Analog or digital information for transmission from the subscriber unit is input to the transceiver where it is modulated onto a carrier signal at a frequency using a modulation code, in the case of the CDMA system, assigned to that subscriber unit. The modulated carrier signal is transmitted from the subscriber unit antenna to the base station. Forward link signals received by the subscriber unit antenna are demodulated by the transceiver and supplied to processing circuitry within the subscriber unit.

Multi-band antenna for wireless applications


Novel peptide compounds and pharmaceutical compositions thereof are disclosed that have a formula represented by the following formula (I) wherein L1, L2, L3, Z, R1, R2, R4 and R5 are as described herein. The compounds demonstrate antimicrobial activity and may be prepared as pharmaceutical compositions and used for the prevention and treatment of a variety of conditions in mammals including humans where microbial invasion is involved. The present peptides are particularly valuable as their effect is rapid, broad in spectrum and mostly indifferent to resistance provided by standard antibiotics.

For the last few decades it has been known that a wide range of antimicrobial peptides are secreted by all manner of multicellular organisms in response to infection by foreign viruses, bacteria or fungi. Current research focuses on the mechanism by which the peptides kill, and synthetic design strategies which can enhance the activity of the peptides to a useful therapeutic level.
A wide range of antimicrobial peptides is secreted in plants and animals to challenge attack by foreign viruses, bacteria or fungi (Boman, 2003). These form part of the innate immune in response to infection, which is short term and fast acting relative to humoral immunity (Medzhitov, 2000). These cationic antimicrobial peptides have been considered as prospective antibiotics agents because their effect is rapid, broad spectrum and indifferent to resistance to standard antibiotics such as penicillins (Fischetti, 2003; Hancock, 1999). However, their success thus far has been limited, and is believed to be due to the requirement that they be present in a fairly high concentration to achieve killing (Hancock, 2000, Proc Natl Acad Sci), which is believed to exert a potentially cytotoxic effect on human erythrocytes as well as other cells and tissues. For these reasons current applications of these peptides are mostly topical.
Hundreds of such antimicrobial peptides have been studied extensively in order to understand the relationship between the structural features of the peptides and their antimicrobial activity, for the purpose of designing a new generation of antibiotics. Such known antimicrobial peptides are listed in The Antimicrobial Peptide Database, accessible via the University of Nebraska Medical Center website, the content and disclosure of which is incorporated herein by reference in its entirety. Representative peptides listed at the site are set forth hereinbelow by way of illustration and not limitation. Known antimicrobial peptides differ strikingly in size, sequence and structure, sharing only amphipathicity and positive charge (Hancock, 1999; Zasloff, 2002). While the external cell wall may be the initial target, several lines of evidence suggest that antimicrobial peptides act by lysing bacterial membranes. Cells become permeable following exposure to antimicrobial peptides, and their membrane potential is correspondingly reduced. While the actual target and mode of action of antimicrobial peptides are incompletely understood, proposed models emphasize the need to coat or cover a significant part of the membrane in order to produce a lethal effect. In "barrel-stave" models, several peptide monomers need to bind before formation of an aggregate that inserts itself into the bilayer to form a transmembrane pore. (Ehrenstein, 1977). In a somewhat different view, known as the "carpet model," peptide monomers must coat the target membrane surface extensively before sections of the membrane split off as vesicles, thereby destroying the integrity of the membrane (Shai, 2001). Both mechanisms account for the observed threshold concentration required for peptides to achieve lethality differently. In many cases this threshold is close to that for inflicting damage on host cells or tissues, as detected by hemolysis assays for example. Thus peptides have not found wide applications except as topical agents.
Several strategies have been pursued in efforts to increase the effectiveness of antimicrobial peptides (Tam, 2002; Janiszewska, 2003; Tam, 2000; Dathe, 2004; Tang, 1999; Dempsey, 2003; Epand, 2004; Papo, 2004). Sequence changes in natural peptides can notably reduce hemolysis while preserving activity (Staubitz, J. Pept. Sci. 2001, 7:552-564). Inserting unnatural D-amino acids or beta-amino acids into peptide sequences, combinatorial designs based on linear or cyclic sequences (Houghton, Ghadiri), synthetic chemical mimetics (DeGrado, Tew), and multivalent dendrimeric constructs of short peptides (Janiszewska, 2003; Xing, 2003) are other alternatives. In some cases improved solubility, salt resistance, stability and toxicity have been reported, with some reduction in IC50 (Tam, 2002). None of the above highlighted references are included in the reference list.
Accordingly, many different designs for therapeutics have been reported, seeking to develop or improve activity under physiological conditions, low toxicity and proteolytic stability. Among promising approaches, polyvalent or multivalent antimicrobial polymers offer promise for enhancing the efficacy of existing antimicrobial monomer peptides and minimizing the problems accompanying conventional antimicrobial peptides by reducing the toxicity of the residue, increasing their efficiency and selectivity, and prolonging the lifetime of the effect. Especially, these include their ability to amplify cationic charges and hydrophobic clusters as the number of monomers increases. (Tam, 2002). For example, the multivalency of peptides incorporated with fragments of known antibacterial peptides in dendrimers has appeared to demonstrate good activity in the design of membranolytic peptides for therapeutic applications (Tam, 2002).
In this connection, U.S. Pat. No. 5,229,490 to Tam discloses a particular polymeric construction formed by the binding of multiple antigens to a dendritic core or backbone, the objective of which is to potentiate the concentration of antigen within a more economical and efficient molecule. While this construction has demonstrated advantages, greater activity and corresponding stability of the construct is still an important objective that is not fulfilled therein.
U.S. Pat. No. 3,679,653 to Schuck et al. discloses the preparation and use of polymer-based protein complexes, and particularly, relates to the preparation of such complexes with hormones such as bovine growth hormone, insulin and the like. Schuck et al. however, prepare complexes with full length native hormones, and bind the native material to the polymer backbone for the purpose of improving the delivery and availability of such hormones. The inventors qualify that the level of activity of the resulting complexes are somewhat uncertain, and in any event, do not represent that any dramatic improvements in such activity are either anticipated or realized.
U.S. Pat. No. 6,063,819 and WO1998/036743 to Marangos et al. disclose peptides attached to tris(2-aminoethyl)amine and tris(3-aminopropyl)amine as neuroprotectants.
US application 2010/0093973 discloses poly(aminoacid) compounds as phosphorus absorption inhibitors.
WO2007/045010 discloses dendrimeric peptides as inhibitors of angiogenesis.
WO2009/025691 discloses dendrimeric peptides as antimicrobials.
US application publication 2007/0053934 discloses polypeptides as antimicrobials.
US application publication 2008/0312159 discloses polypeptides as antimicrobials.
Antimicrobial peptides (AMPS) have been proposed as prospective antibiotic agents because of their ability to rapidly inactivate a wide range of microorganisms including Gram-positive and negative bacteria, fungi and some viruses. In many cases they are indifferent to current multi-drug resistant strains (Hancock and Chapple 1999; Lehrer and Ganz 1999). From the above, it remains that a continuing need exists for the development of modalities that can deliver effective antibiotic peptides in a manner that confers both improved stability and economy of the therapeutic, but importantly, significantly improves the therapeutic efficacy and strength of the resultant molecule. It is toward the fulfillment of these and other related objectives that the present invention is directed.

Dendrimeric peptides, pharmaceutical compositions and methods of using the same


A thermal interface material includes a matrix and carbon nanotubes. The matrix includes a first surface and an opposite second surface. The carbon nanotubes are embedded in the matrix uniformly. The carbon nanotubes extend from the first surface to the second surface, and each carbon nanotube has two opposite ends. At least one of the two opposite ends of the carbon nanotubes are exposed out of one of the first and second surfaces of the matrix. The exposed ends of the carbon nanotubes are elastically bent/embedded in a phase change layer formed thereon.

1. Technical Field
The invention relates generally to thermal interface materials and methods for making them; and more particularly to a thermal interface material which conducts heat by using carbon nanotubes, and a method for making such thermal interface material.
2. Discussion of the Related Art
Electronic components such as semiconductor chips are becoming progressively smaller, while at the same time heat dissipation requirements thereof are increasing. Commonly, a thermal interface material is utilized between the electronic component and a heat sink in order to efficiently dissipate heat generated by the electronic component.
A conventional thermal interface material is made by diffusing particles with a high heat conduction coefficient in a base material. The particles can be made of graphite, boron nitride, silicon oxide, alumina, silver, or other metals. However, a heat conduction coefficient of the thermal interface material is now considered to be too low for many contemporary applications, because it cannot adequately meet the heat dissipation requirements of modem electronic components.
A new kind of thermal interface material has recently been developed. The thermal interface material is obtained by fixing carbon fibers with a polymer. The carbon fibers are distributed directionally, and each carbon fiber can provide a heat conduction path. A heat conduction coefficient of this kind of thermal interface material is relatively high. However, the thickness of this kind thermal interface material is limited to be greater than 40 micrometers, and the heat conduction coefficient of the thermal interface material is inversely proportional to a thickness thereof. In other words, the heat conduction coefficient is limited to a certain value corresponding to a thickness of 40 micrometers. The value of the heat conduction coefficient cannot be increased, because the thickness cannot be reduced.
An article entitled "Unusually High Thermal Conductivity of Carbon Nanotubes" and authored by Savas Berber (page 4613, Vol. 84, Physical Review Letters 2000) discloses that a heat conduction coefficient of a carbon nanotube can be 6600 W/mK (watts/milliKelvin) at room temperature.
U.S. Pat. No. 6,407,922 discloses another kind of thermal interface material. The thermal interface material is formed by injection molding, and has a plurality of carbon nanotubes incorporated in a matrix material. A first surface of the thermal interface material engages with an electronic element, and a second surface of the thermal interface material engages with a heat sink. The second surface has a larger area than the first surface, so that heat can be uniformly spread over the larger second surface.
However, the thermal interface material formed by injection molding is relatively thick. This increases a bulk of the thermal interface material and reduces its flexibility. Furthermore, the carbon nanotubes are disposed in the matrix material randomly and multidirectionally. This means that heat does not necessarily spread uniformly through the thermal interface material. In addition, the heat does not necessarily spread directly from the first surface engaged with the electronic element to the second surface engaged with the heat sink.
What is needed, therefore, is a thermal interface material that has a low thermal interface resistance and a high heat conducting efficiency.
What is also needed, therefore, is a method for making the above-described thermal interface material.

Thermal interface material and method for making the same


An apparatus for temporarily sealing a vent or overflow aperture provided in the upper portion of a fixture such as a wash basin, sink, bathtub or bidet so that a pneumatic or hydraulic type sewer cleanout device can be used to clear a blockage located in a sewer line downstream of the fixture by generating fluid pressure within the sewer line intermediate the blockage and the main water drain of the fixture.

1. Field of The Invention
The present invention relates generally to devices for sealably closing vent apertures provided in the walls of various types of fixtures. More particularly, the invention concerns a device for use in temporarily sealing vents or overflow drains of the character typically provided in the upper wall portions of fixtures such as wash basins, sinks, bathtubs, and bidets.
2. Discussion of The Invention
In recent years several hydraulic and pneumatic devices have been developed for clearing blockages in drain lines by forcing fluids under pressure through the water outlet drain of the fixture. Such devices may force water or other liquids under pressure through the drain outlet, or they may be of the pneumatic impact or "air hammer" type which forces compressed air or other gases through the drain and into the sewer line.
Prior art cleanout devices of the aforementioned character lose their effectiveness when used with fixtures having a vent or overflow drain apertures. Such apertures are usually provided in the upper portions of the fixture and function to drain water from the fixture into the drain line connected to the drain outlet if the fixture is accidentally over filled. The overflow drain apertures are, of necessity, in communication with the sewer drain line which, in turn, is in communication with the fixture drain, or outlet. When a fluid pressure type cleanout device is used to clear a blockage in the drain line, the overflow apertures must be sealed. Otherwise the fluid forced through the fixture drain under pressure can flow outwardly through the overflow drain apertures before sufficient fluid pressure can be exerted against the blockage to open the line to normal water drainage from the fixture.
In many instances, the overflow apertures provided in a given fixture are in communication with an internal fluid passageway defined between inner and outer, spaced apart walls. The inner wall of the fixture typically defines the water reservoir while the outer wall defines the exterior surfaces of the fixture. Since, with this type of construction, the overflow apertures are accessible only from the inside of the fixture, effective sealing of the apertures can be difficult. For this reason, most types of prior art overflow drain seals involve the use of tapered plugs which can be inserted into the overflow apertures from the interior of the bowl of the fixture. However, such plugs are typically ineffective in sealing the overflow apertures against fluid pressure which is built up interiorly of the walls of the fixture by fluid pressure type cleanout tools. In instances of stubborn blockage of the sewer drain line, the cleanout tool will generate sufficient pressure within the internal passageway of the fixture to blowout the sealing plugs before clearing the blockage in the line. When this occurs the plugs, along with the backed up fluid, can be ejected with a force that can cause serious personal injury and cause cost property damage.
The purpose of the present invention is to provide a simple, easy to use apparatus which can be employed to effectively seal overflow drain apertures provided in a given fixture against even substantial fluid pressures which may be generated against the sealing member of the apparatus by a pressure type sewer line cleanout tool. Because of the unique design of the apparatus of the invention, it can effectively be used with fixtures of widely varying designs and configurations.


A server computer receives a user identifier from a user computer web browser program. The server computer identifies one or more uncompleted tasks associated with the user identifier that can be completed from the user computer via the user computer web browser program. The server computer then transmits to the user computer one or more universal resource locators (URLs) associated with the one or more uncompleted task, and the user computer provides access to the web pages referenced by the one or more URLs via the user computer web browser program. In certain embodiments, the server computer identifies the one or more uncompleted tasks by accessing a database that includes uncompleted tasks by user identifier and a URL associated with each uncompleted task. In other embodiments, the server updates the database when an uncompleted task associated with a user identifier is completed.

Many business enterprises maintain websites that are designed specifically to support an enterprise's business activities. These websites can host content that includes informational content directed to current and potential customers, online customer order entry applications, and other applications directed to customer interactions. Enterprise websites can also host information and applications directed to the enterprise's employees. For example, an enterprise may maintain an internal website that includes information related to the enterprise's business strategies, internal development documents, personnel policies, etc. The internal website may also include information related to activities or tasks employees are assigned to complete. For example, all employees of the enterprise may be assigned to complete a training course related to export regulations, or employees of a certain division may be assigned to complete a training course related to products developed by the division. Enterprises often have systems in place to send out email reminders to employees who have not completed assigned tasks and courses by associated due dates.
The use of web browsers is commonplace in the business environment, partly as a result of the popularity of internal enterprise websites. Popular web browsers include Firefox by Mozilla Corporation, Internet Explorer by Microsoft Corporation, Chrome by Google Inc., and Safari by Apple Inc. A feature that is available in almost all web browsers is the ability to open multiple tabs in a single browser window. This feature allows the user to open multiple web pages within a single instance of a web browser without having to open a new browser window for each web page. In addition, the feature allows the user to easily switch between open web pages by selecting among the browser tabs. A web browser can also open a browser tab based on information contained in web pages received by the web browser. For example, certain HTML (hypertext markup language) and JavaScript statements in a web page received by a web browser can cause a new tab to be opened in the web browser.

Browser start pages based on remote content

International Business Machines Corporation


A microscale sampling device including a frame is provided in the present invention, a sample container, a communicating channel and a resistance channel are defined in the frame. At least one sampling chamber is defined in the communicating channel. An end of the communicating channel is communicated with the sample container and the communicating channel is arranged below the sample container. An end of the resistance channel is communicated with the sampling chamber, and the other end of the resistance channel is communicated to an output joint. The resistance channel is shaped with at least one discontinuous shape change.

A conventional automatic biological testing equipment is used for taking a specific quantity of target sample from a specific sample reservoir and transferring to another reaction chamber. This sampling process is one of the most important processes of the whole biochemical reactions. Usually, a conventional large equipment performs the aforementioned sampling process by a three-axis robot with a pipettor. However, the large equipment cannot be used on POCT (Point of Care Testing) because of its size, and its sampling chamber and transferring route for the sample are open. Therefore, the sample might be contaminated, and the test results might perform pseudo-positive or pseudo-negative.
A conventional micro channel sampling device is used for accurately sampling a specific quantity of sample for dispensing, and is divided to two types: electrical control type and physical control type. The electric control sampling device is suitable for detecting a sample containing polarizable liquid or particles, the sample is polarized to produce electrophoretic or dielectrophoretic forces, and a specific quantity of sample thereby could be taken accurately. The electric control sampling device is usually applied to electrophoresis analysis of DNA or RNA. However, the sample should withstand serious electric field change and should be polarizable, and the electric control sampling device is therefore only applied to specific types of sample. Furthermore, components of the sample for the electrical control programs process should be accurately controlled. However, component proportion of clinical samples are difficult to be accurately controlled and therefore unsuitable for the electric control sampling device.
The physical control sampling device is able to accurately take a specific quantity of sample by mechanical structure (pipe) and physical control (gas driving or mechanical driving). The physical control sampling devices are commonly used sampling devices. However, the physical control sampling device only operates single sampling and dispensing process at the same time and therefore unsuitable for group sampling.
In views of this, in order to solve the above disadvantage, the present inventor studied related technology and provided a reasonable and effective solution in the present invention.


A mounting structure for an automobile footrest whereby a footrest can be mounted in a condition with no rattle by a perfectly one-touch operation comprising plate-shaped mounting members mounted with prescribed separation on an automobile body panel and provided with respective engagement parts, and a footrest mounted on these plate-shaped mounting members. The footrest is provided on its rear face with mounting parts capable of engagement in sliding relationship with respective plate-shaped mounting members. These mounting parts are respectively provided with engaging claw structures that resiliently engage engagement parts of the plate-shaped mounting members and are arranged with a separation corresponding to the mounting separation of the plate-shaped mounting members on the vehicle body.

This invention relates to a mounting structure for an automobile footrest.
Conventionally, nuts and bolts were usually employed for the mounting of automobile footrests. However, with this method of mounting, a large number of steps are required in the mounting operation, and improvement is desired. Consequently, in order to facilitate mounting of footrests, a construction has been proposed, for example in Japanese Utility Model Publication No. H.6-6999, wherein a threaded stud is fixed by welding or the like to an automobile body, and the footrest is mounted by means of a clip provided with an engagement claw that engages the threaded part of this stud. However, with this construction, a mounting clip separate from the footrest must be employed, so a perfect one-touch operation cannot be achieved. Also, with mounting using a stud, rattling in the mounted condition cannot be satisfactorily prevented, so a large peripheral flange of the footrest has to be employed, this flange being pressure-fixed to an automobile panel; this is inconvenient in use.

Mounting structure for automobile footrest


A field emission type backlight device with high light efficiency may include a front substrate, a reflective substrate on the front substrate, a rear substrate separated from the front substrate by a predetermined gap, anode electrodes provided with a predetermined gap between them on the rear substrate, a light-emitting layer on the anode electrode, a cathode electrode and a gate electrode spaced apart on the rear substrate between the anode electrodes, and an electron emission source emitting electrons by electric field on the cathode electrode.

This application claims the priority of Korean Patent Application No. 10-2004-0004441, filed on Jan. 20, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a field emission type backlight device, and more particularly to a field emission type backlight device for a liquid crystal display (LCD) apparatus.
2. Description of the Related Art
An LCD apparatus has a backlight device in a rear side which typically supplies a white light. A cold cathode tube has been commonly used as a backlight device. Flat panel backlight devices, however, are required for thinner LCD apparatuses.
FIG. 1 is a sectional view showing a configuration of a conventional backlight device for the LCD apparatus.
A spacer (not shown) is provided between a front substrate 1 and a rear substrate 4. The space between the front substrate 1 and the rear substrate 4 is sealed with a wall (not shown). A cathode electrode 5 is provided in plane or stripe on the rear substrate 4. A field emission source such as a carbon nanotube (CNT) 6 is provided on the cathode electrode 5. On the front substrate 1 is an anode electrode 2, which is generally a transparent electrode. A light-emitting material 3 (which may be a fluorescent material) is deposited on the anode electrode 2.
When a predetermined voltage is applied between the cathode electrode 5 and the anode electrode 2, electrons are emitted from the field emission source 6 to excite the light-emitting layer 3. Light from the light-emitting layer 3 is incident on the LCD apparatus through the light-emitting layer 3, the anode electrode 2, and the front substrate 1.
A conventional flat panel backlight device can have non-uniform luminance because of a concentration of electron emission in the edge of the cathode electrode 5. In addition, since light is to be supplied to the LCD apparatus through the light-emitting layer 3 and the front substrate 1, light transmittance can be reduced due to the light-emitting layer 3. The bigger the LCD apparatus grows large in size, the bigger the non-uniformity in luminance.
There is a field emission device with good energy efficiency. For instance, in U.S. Pat. No. 5,760,858, a triode-structure field emission device is combined with a liquid crystal panel, so that it is possible to obtain a low power consuming backlight. In addition, it is possible to obtain uniform high luminance because the field emission device is in a surface emission mode.
However, the backlight device described in U.S. Pat. No. 5,760,858 has almost the same structure as a Spindt-type field emission display (FED). The Spindt-type field emission structure is fabricated at the same time when a liquid crystal panel is fabricated, and thus its fabricating process is complex. Moreover, since the field emission structure is fabricated using semiconductor fabricating processes, its production cost is high and its production yield is low.


The present disclosure provides an artificial neural network system for identifying a lesion in a retinal fundus image that comprises a pre-processing module configured to separately pre-process a target retinal fundus image and a reference retinal fundus image taken from a same person; a first neural network (12) configured to generate a first advanced feature set from the target retinal fundus image; a second neural network (22) configured to generate a second advanced feature set from the reference retinal fundus image; a feature combination module (13) configured to combine the first advanced feature set and the second advanced feature set to form a feature combination set; and a third neural network (14) configured to generate, according to the feature combination set, a diagnosis result. By using a target retinal fundus image and a reference retinal fundus image as independent input information, the artificial neural network may simulate a doctor, determining lesions on the target retinal fundus image using other retinal fundus images from the same person as a reference, thereby enhancing the diagnosis accuracy.

An artificial neural network is a machine learning model that simulates the human brain structure. With the development of artificial neural networks, especially artificial intelligence technology such as deep learning, the application of artificial neural networks in the field of medical imaging diagnosis is drawing more and more attention. By using such an artificial neural network, potential lesions can be automatically determined based on medical images, i.e., automatic screening can be done on the medical images. For example, artificial neural networks such as deep learning have been studied in various fields, such as breast cancer pathological analysis, lung cancer detection, cardiovascular imaging and the like.
Medical images, which are usually obtained by means of a camera, an x-ray transmission machine, CT, OCT, MRI and the like, may contain numerous details of body structures or tissues, and identifying such details in a medical image may assist a doctor with relevant diagnosis. Taking retinal fundus images among medical images for example, a retinal fundus image contains abundant details of vitreous body, retinal, choroid and the like, and if there are related lesions, changes such as microangioma, bleeding, hard exudates and the like will be presented in the retinal fundus image. Among those lesions, diabetic retinopathy, for example, as a common retinal fundus lesion, is one of the diabetic complications, and has become one of the main causes of blindness of the working-age population. It is estimated there are 92.4 million diabetic patients in China with a five-year incidence of 43% and a blindness rate of 10%. Various researches indicate that early diagnosis and treatment of the diabetic retinopathy can effectively control or even alleviate the visual impairment of a patient. Therefore, regular retinal fundus disease screening in diabetic patients is important to our society. However, conventional diabetic retinopathy screening requires specialized ophthalmologists to observe retinal fundus images by eyes to make a diagnosis, resulting in high work load and cost, which is not good for the applications in a large scale. Meanwhile, retinal fundus screening requires a doctor to read a large number of retinal fundus images in a short time, and may be too tired to keep the diagnosis accuracy at a high level. Therefore, there is an urgent need for the computer-based automatic screening (automatic image reading) using artificial intelligence algorithms.
At present, such researches have been done or being carried out by scientific research teams. For example, non-patent document 1 discloses a method for diagnosing diabetic retinopathy by artificial intelligence, where a well-known deep learning network structure, Inception-v3, is used, and a high accuracy is achieved. It at least achieves the effect of replacing part of a professional ophthalmologist's work.
In addition, patent document 2 discloses a method, a device and a system for processing a retinal fundus image based on deep learning. In the patent document 2, a conventional convolutional neural network is employed to analyze an image. In particular, a resampled retinal fundus image is input, and a seven-layer convolutional neural network containing five convolutional layers and two fully connected layers is employed for identification.

Artificial neural network and system for identifying lesion in retinal fundus image