An integrated circuit has circuitry formed by a fabrication process. The circuitry has an electrical characteristic that is different from a predetermined value due to variations in the fabrication process. The electrical characteristic is responsive to a level of a current, and a current source of the integrated circuit is configured to be selectably enabled to adjust the level of the current to move the electrical characteristic closer to the predetermined value.

The invention relates to trimming an integrated circuit, such as a silicon temperature sensor.
The electrical characteristics (e.g., bias voltages and currents) of an integrated circuit typically are functions of parameters of a process that is used to fabricate the circuit. The parameters might include resistivities and threshold voltages, for example, and the process might be, for example, a CMOS process. Engineers typically take into account ideal parameters of the process when designing and laying out the integrated circuit.
The actual electrical characteristics of the circuit should match the designed characteristics. However, quite often, process fabrication variations cause the actual parameters of the process to vary. As a result, the actual electrical characteristics of the integrated circuit are different from the designed characteristics. Although some circuits are designed to have a minimum sensitivity to process variations, other circuits are by their very nature quite sensitive to process variations.
After fabrication, a technique called trimming is typically used to compensate for process variations. For example, the resistance of an integrated resistor (e.g., an n-well resistor) might vary up to fifty percent from the designed value. Referring to FIG. 1, to adjust, or trim, the resistance of a resistor 2 after fabrication, quite often a nonlinear trimming technique is used to adjust the effective resistance of the resistor by selectively coupling trimming resistors 3 (via transistors 4) in parallel with the resistor 2. However, a difficulty with this technique is that the trimming is nonlinear. Therefore, to properly trim the resistor 2, a considerable number of resistors 3 might be needed, and thus, a large amount of die space may be consumed for trimming purposes.
Because each resistor 3 generally consumes a considerable amount of die area (versus a transistor, for example), the above-described trimming technique is quite often limited by the available area in the die. Furthermore, it is quite often difficult to trim the resistance near the desired valve due to the large tolerances of the resistors 3 and the resistance introduced by the channel resistance of the transistor 4. The channel resistance of the transistor 4 is a function of a threshold voltage (typically referred to as V.sub.T) which is a process parameter that is also subject to variation.
Referring to FIG. 2, an example of a circuit that is typically sensitive to process variations is a thermal sensor 8. The sensor 8 might, for example, monitor a substrate temperature of a microprocessor. When the temperature exceeds a predetermined threshold temperature (e.g., 100.degree. C.), the sensor 8 alerts other circuitry of the microprocessor so that corrective action (e.g., throttling back or shutting down of the microprocessor) may be taken to reduce the temperature. Without the corrective action, the substrate may overheat, and catastrophic failure of the microprocessor may occur.
The sensor 8 typically must precisely sense the temperature to avoid generating false alarms when the temperature is below the predetermined threshold temperature. These false alarms might slow down or shut down a microprocessor that is otherwise behaving normally.
For purposes of determining when the threshold has been exceeded, the thermal sensor 8 typically has a comparator 10 that electrically compares the temperature of the substrate to the threshold. To accomplish this, the comparator 10 receives a thermal trip point signal (called V.sub.REF) that electrically represents the predetermined temperature threshold. The comparator 10 also receives a signal (called V.sub.SENSE) that represents a measured temperature of the substrate. The comparator 10 compares the V.sub.REF signal which typically has a positive temperature coefficient with the V.sub.SENSE signal which typically has a negative coefficient. Typically, the V.sub.SENSE signal is furnished by a diode.
The DC voltage level of the V.sub.REF signal typically represents the predetermined temperature threshold. However, this voltage level is sensitive to process variations. As a result, the V.sub.REF signal may not accurately represent the threshold, and thus, the overall accuracy of the sensor 8 may be limited by the process variations.
Thus, there is a continuing need for an integrated circuit that allows accurate, post fabrication trimming of the circuit.

Method and apparatus for trimming an integrated circuit


A water filter assembly including a water filter housing and a manifold coupled to the water filter housing. The manifold includes an inlet and an outlet. Filters are disposed in the water filter housing. The water filter assembly has a door. The door is disposed on the water filter housing providing selective access to the water filter housing. The door is connected to the water filter housing to open and close to replace the plurality of filters. The water filter assembly also has a valve associated with at least one of the plurality of filters. The valve is manipulated from an opened to a closed position to close the inlet when the filters are removed from the water filter housing.

The present disclosure relates generally to a water filter assembly. More particularly, the present disclosure relates to a water filter assembly that is hidden from view on an exterior surface of a refrigerator and that includes multiple filters disposed in a cartridge that can be easily replaced.
A refrigerator typically includes a water dispenser that dispenses filtered water from a water source. Sometimes the water dispenser is placed in a door of the refrigerator. The user takes a glass and pushes a lever or actuates a button to dispense filtered and chilled water. After a period of time, the filter associated with the water dispensing assembly is required to be replaced with a fresh filter as the prior filter becomes accumulated with impurities. Some configurations place the water filter assembly in an interior of the refrigerator. This configuration is disfavored as placing the water filter assembly in the interior of the refrigerator reduces the overall volume of storage space of the refrigerator. Additionally, a heating device may be required if the water filter assembly is located in the interior since ducting is needed to circulate water to and from the water filter assembly and the filtered water in the ducting may freeze if placed too close to the freezer compartment. Moreover, some other configurations will place the filter in an inconvenient location, such as a rear of the unit. The refrigerator is quite large and heavy usually and the user will be reluctant to move the refrigerator to access the rear. Also, by placing the water filter in the rear or in an area that is somewhat hidden, the user will not notice that the water filter requires replacement. Additionally, placing the water filter assembly in an interior location in the rear of the unit may even necessitate special tools to replace and open the water filter assembly to remove and replace the filter, which is disfavored and will discourage replacement.
There is a need in the art for a water filter assembly that can be quickly and easily replaced and that cuts the water supply to the water filter assembly during replacement. There is a need in the art for a water filter assembly where the water filter cartridge can be replaced in minutes to encourage replacement. There is also a need for a water filter assembly that has a narrow profile and that can be hidden from view when the refrigerator doors are closed. There is also a need for a water filter assembly that includes at least two filters in a narrow profile and that is disposed on an exterior surface and that does not take up any interior space of the refrigerator, which is highly valued. There is also a need for a water filter assembly that includes an easy and quick filter replacement functionality that does not require special tools. There is a further need for a water filter assembly that encourages replacement and does not require extensive instructions or removal of components of the refrigerator to access the water filter assembly.


At least one exemplary embodiment is directed to a zoom lens which includes a first lens group, which can have a positive refracting power; a second lens group, which can have a negative refracting power, and can move during zooming; a third lens group, which can have a positive refracting power; and a fourth lens group, which can have a positive refracting power, and can move during zooming, the lens groups being aligned in order from front to back, where the focal lengths fw and ft of the whole system at a wide-angle end and at a telescopic end, respectively, can satisfy the following conditions:0.15<fw/f4 <0.261.0<f3/(fw·ft)1/2<1.2.

1. Field of the Invention
The present invention relates to zoom lenses, more particularly, though not exclusively, the present invention relates to zoom lenses that can be used as image-taking lenses in imaging apparatuses.
2. Description of the Related Art
In optical imaging systems used for imaging apparatuses such as video cameras using solid-state image-pickup devices, digital still cameras, and silver-salt film cameras using silver-salt films, the desirability of compact-system zoom lenses having optical performance of high resolution have increased.
Since video cameras capable of recording still images of high definition have also been increasingly required, the desirability of lens systems that are compact yet having high-optical performance have increased.
One such zoom lens system that can be used includes four lens groups consisting of a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, and a fourth lens group having a positive refracting power, the lens groups being aligned in order from (the anterior position adjacent to) an object side to an image side (the posterior position adjacent to an image taking side). This zoom lens is known as a four-group zoom lens of a so-called rear-focus type in which the second lens group moves so as to change magnification and the fourth lens group adjusts the focus while correcting and/or reducing image-plane fluctuations generated by the magnification changes. Such a zoom lens is discussed in Japanese Patent Laid-Open Nos. 08-304700, 2000-121941, and 2003-295053.
Zoom lenses of the rear-focus type are characterized by small driving power for lens groups and rapid focusing since the lens groups that move to focus are equivalently small and lightweight.
In such zoom lenses of the rear-focus type, a compact zoom lens including a minimum number of lenses has been discussed in Japanese Patent Laid-Open No. 05-027167 and U.S. Pat. No. 6,441,968.
A zoom lens discussed in Japanese Patent Laid-Open No. 05-027167 has a structure that can be used for ⅓-inch and ¼-inch image-pickup devices. In particular, the number of lenses can be reduced by using a plurality of aspherical lenses.
In Japanese Patent Laid-Open No. 05-027167, chromatic aberration may not be sufficiently corrected since the fourth lens group includes only one positive lens. Therefore, a zoom ratio up to 8 times causes no problem, but a zoom ratio higher than or equal to 20 times can lead to large fluctuations of the chromatic aberration during focusing adjacent to the telescopic end.
As in the case of Japanese Patent Laid-Open No. 05-027167, the fourth lens group includes only one positive lens in U.S. Pat. No. 6441968, and thus the chromatic aberration may not be sufficiently corrected. Moreover, the third lens group has a strong refracting power in U.S. Pat. No. 6,441,968, and accordingly, the curvature radii of positive lenses in the third lens group are small. Therefore, when the brightness at a wide-angle end is higher than F1.8, optical performance at the wide-angle end becomes more difficult to be retained satisfactorily. Furthermore, the external diameters of the lenses can become large with the aperture ratio, and the thicknesses of the lenses in the centers can be increased as the curvature radii of the positive lenses become small for ensuring the thicknesses of the lenses in the outer portions, resulting in an increment in size of the whole lens system.
When the refracting powers of the lens groups for changing magnification are enhanced in the zoom lenses, moving distance for a predetermined zoom ratio becomes short. Accordingly, high variable power (high zoom ratio) can be achieved while the total length of the lenses is reduced.
However, when the refracting powers of the lens groups are merely enhanced without appropriately setting the configurations of the lens groups, aberration fluctuation during zooming becomes large, thus making it difficult to achieve excellent optical performance over the whole variable-power range when high variable power is required.

Zoom lens and imaging apparatus including the same


The subject invention provides an expedited synthesis of 5, 6, and 7-iodoindenes from the corresponding aminoindan-1-ones in more than 70% yield, employing readily available precursors and reagents. A three-step sequence involves diazotization-iodination of aminoindan-1-one followed by reduction and dehydration. The method has a general character and can be extended for the preparation of various 4-, 5-, 6- or 7-haloindenes using different halogen sources for diazotization-halogenation reaction.

The haloindenes are convenient precursors in organic and biologically-targeted syntheses. For example, 6-bromoindene is used to prepare ethylene-bis (indenyl) ligand via Suzuki coupling. The 4-, 5-, or 6-bromo (or chloro)indenes are utilized in the synthesis of inhibitors of the Na+/H+ exchanger and histone lysine specific demethylases. Moreover, 5- and 6-bromoindene are used to study the mechanism of dioxygenase-catalyzed benzylic hydroxylation of indene. The 6-chloroindene serves as precursor for the synthesis of 6-chloro-N-hydroxy-1H-indene-2-carboxamide, used to study the structure-activity relationships of neurotoxin A protease inhibitors, as well as fullerene-based photovoltaic acceptor materials. Haloindenes can also be used to synthesize halo-substituted isoquinoline derivatives. Indene molecule (C9H8) has received considerable attention from the combustion and physical (organic) chemistry communities as a potential building block of non-planar polycyclic aromatic hydrocarbons (PAHs) such as corannulene (C20H10)—a precursor to fullerenes such as C60 and C70. Different indenyl radicals can act as a precursor for the molecular mass growth process to form non-planner PAH.
Pyrolysis of bromoindenes produces resonance-stabilized and thermodynamically most stable 1-indenyl π radical which was found to be non-effective precursor for the molecular mass growth processes of PAH in extraterrestrial and combustion environments.
There is only one method for the preparation of more reactive 5- or 6-iodoindene, which requires expensive intermediates and several steps. The reported yields for 5- or 6-iodoindenes were only 20% and 7% (Miller, R. B.; Frincke, J. M. Synthesis of isoquinolines from indenes. J. Org. Chem 1980, 45, 5312). The 5-nitroindene and 6-nitroindene were used as precursors for such preparation, respectively.
Thus, there is a need for developing methods for synthesizing haloindenes, in particular, iodoindenes including 4-, 5-, 6-, and 7-iodoindenes isomers, with high yield and purity, which are simple and do not require the use of expensive and/or unstable reagents and/or intermediates.

THE FLORIDA INTERNATIONAL UNIVERSITY BOARD OF TRUSTEES


Methods and apparatus for detecting the onset of stress corrosion cracking are described. In one aspect, the present invention is a passive detector for in-situ detection of the onset of stress corrosion cracking in a nuclear reactor. The detector includes a ceramic insulator mounting member. A first material sample and a second material sample are secured to the mounting member. In the one embodiment, a metal bolt extends through the first and second material samples and secures the samples to the mounting member. The first material sample is cold worked to induce residual tensile stress and the second material is not cold worked. A first electrical conductor is electrically connected to the first material sample and a second electrical conductor is electrically connected to the second material sample. An electrometer is electrically connected to the first and second electrical conductors, and the electrometer is configured to generate a strain induced differential potential signal representative of a difference in potential between the first sample and the second sample. Alternatively, a strain induced differential current signal can be monitored using a zero resistance ammeter in place of the electrometer. The detector configured to be located within the reactor at the location where monitoring is desired, and during the reactor operation, if transients are observed in the differential signal, this condition indicates that at the location of the detector, an inspection should be performed at the next outage to determine whether cracking is occurring. Active detectors, detection methods, and test apparatus also are described.

The detection of early stages of stress corrosion cracking initiation has been a subject of great interest to the corrosion community, particularly to those in the nuclear industry. Such early detection of cracking would enable one to take corrective action before the occurrence of major component failures. Particularly in a nuclear reactor, it is highly desirable and imperative to prevent major component failure.
The most commonly known stress corrosion cracking detection approach is to use a constant extension rate tensile (CERT) test. In a CERT test, a dog bone type tensile specimen is stressed at a constant extension rate within an autoclave containing the corrosive environment. The test is interrupted at known % strains, and at each interruption, the specimen is examined for crack initiation. The crack initiation process has been studied, using CERT tests, as a function of water temperature, heat treatment temperature, cold work, etc.
Although CERT tests provide very valuable information, a shortcoming of the CERT test technique is the need to periodically remove the specimen from the high temperature autoclave for microscopic examination to detect the initiation of stress corrosion cracks. Removing and inspecting the specimen adds time and expense to the testing operations. In addition, the CERT test approach cannot be used as an in-situ tool for the early detection of stress corrosion cracks in the environment.
It would be desirable to prevent major component failure due to stress corrosion cracking by early detection of the initiation of such cracking. It also would be desirable to provide an in-situ method and device for crack detection in a reactor and other environments.

Methods and apparatus for detection of crack initiation


A solid support for the solid-phase synthesis of peptides or proteins in high yield and in high purity, suited both to the synthesis of a single peptide or protein and to the parallel and substantially simultaneous synthesis of a plurality thereof, is based on a cross-linked polyolefin, especially polyethylene, substrate, the cross-linking having been obtained by irradiation with high energy electrons or .gamma. radiation or treatment with organic peroxide such as benzoyl peroxide, to which substrate are grafted polymer chains such as polystyrene chains which are functionalized with a chemical functionality facilitating the formation of an anchoring linkage between the polymer moiety and another chemical species. The solid support is also suited for use in solid-phase biosystems, notably bioassays, such as immunoassays, DNA hybridization assays or PCR amplification. The grafted chains may bear substituents which are such that the polymer-grafted cross-linked polyolefin substrate is swellable by water or aqueous media, in other words, hydrophilic, which makes the solid support particularly well suited for assays of the ELISA type.

Until quite recently, solid-phase methods for the synthesis of peptides or proteins have to a large extent been based on the original methodology developed by Merrifield, employing a functionalized cross-linked styrene/divinylbenzene copolymer, the cross-linked copolymer having been formed by the polymerization of styrene monomer to which has been added a few per cent (typically about 2%) of divinylbenzene. This copolymer is generally provided in the form of beads or particles, often with a dominant particle size of 20-80 .mu.m. The functionalization originally preferred by Merrifield see e.g. J. Am. Chem. Soc. 85, 2149 (1963)! was a functionalization of the aromatic rings of the copolymer with chloromethyl groups, introduced via reaction of the solid copolymer with SnCl.sub.4 /chloromethyl methyl ether, although a number of other functionalities, including aminomethyl, .alpha.-aminobenzyl and .alpha.-amino-4-methylbenzyl, have subsequently been employed. Regardless of its nature, the purpose of the functionality is normally to form an anchoring linkage between the copolymer solid support and the C-terminal of the first amino acid which it is desired to couple to the solid support. Later refinements of the Merrifield methodology have included the further introduction, between a functionality (e.g. one of the above-mentioned functionalities) on the polystyrene chains and the C-terminal of the first amino acid which is to be coupled, of a bifunctional "spacer" or "handle" group whose reactivity is tailored inter alia to meet desired requirements with respect both to the coupling of the first amino acid to the solid support and/or to the ease with which the completed, synthesized peptide or protein chain is cleaved from the solid support. Examples of such spacer groups include the phenylacetamidomethyl (Pam) and the p-alkoxybenzyl ester systems. Barany et al. Int. J. Peptide Protein Res. 30, 705-739 (1987)! have reviewed the development of solid-phase peptide synthesis methodology from its introduction by Merrifield up to about 1986.
The advances in biotechnology which have been made in the last decade or so, particularly in the area of recombinant DNA, have produced a situation in which vast numbers of new protein sequences with undefined or unknown function and/or unknown biological activity have become available. In this connection, detailed structural analysis by site-directed mutagenesis or similar molecular engineering techniques has provided a useful approach to the study of the roles of amino acid residues in active sites of proteins.
However, specific information concerning biologically active functional subunits (peptides) containing ca. 5-40 amino acid residues is preferably obtained through chemical synthesis. Whilst the chemical methodology which had been developed within the period reviewed by Barany (vide supra) was quite capable of yielding such peptides reliably and in high purity when using the above-outlined "conventional" method of solid-phase peptide synthesis (via a "linear" mode of approach), only one peptide was produced per synthesis.
A greater need than ever thus arose for methods employing a "simultaneous" or "parallel" mode of approach to the synthesis of peptides so that a large number of peptides could be synthesized simultaneously (or substantially simultaneously). These peptides could then be used, for example, to define and map the functional entities of proteins. The obvious advantages of a method permitting the parallel and substantially simultaneous synthesis of a multitude of peptides are the attendant saving in time, and the redundancy of the repetitive labour involved in accomplishing the synthesis of each peptide individually.
In this connection, a basic feature of the solid-phase technique of peptide synthesis is that in each elongation of the peptide chain with a further amino acid, all treatment steps are repetitive of the previous cycle with the possible exception of the amino acid coupling step itself, in which a further amino acid that may or may not be identical with that coupled in the preceding cycle is coupled to the peptide chain. Thus, parallel, substantially simultaneous synthesis of two or more peptides could be achieved by performing in parallel the repetitive steps, such as deprotection, neutralization, and washing, which are common to the parallel syntheses. The major technical difficulty here had been the attainment of compartmentalization of each amino acid coupling step so that cross-contamination did not occur.
Several different methods have been proposed for the substantially simultaneous synthesis of a number of peptides:
One of these methods Geysen et al., Proc. Natl. Acad. Sci. USA. 81, 3998-4002 (1984) and 82, 178-82 (1985)! was devised for rapid screening of peptide epitopes via ELISA (Enzyme Linked Immunosorbent Assay) in 96-microtiter wells. It utilizes acrylic acid-grafted polyethylene rod-and-96-microtiter wells to immobilize growing peptide chains and to perform the compartmentalized synthesis. However, while highly effective, the method is not applicable on a preparative scale, i.e. to the preparation of milligram quantities.
A second method Houghten, Proc. Natl. Acad. Sci. USA. 82, 5131-35 (1985)! utilizes a "tea bag" containing the traditionally used polymer beads to compartmentalize the synthesis, portions of peptidyl-resin beads being kept apart in sealed bags of fine-mesh polypropylene net. The latter method is relevant to the preparation of milligram quantities.
A more recent, and highly effective, third method is disclosed in WO 90/02749. The basic method of peptide synthesis disclosed therein uses a polymer substrate--especially a polyethylene substrate--which is preferably in the form of a sheet or film, and to which polystyrene chains have been grafted. The polystyrene chains, which may bear further substituents which are not reactive under the conditions prevailing in the synthesis, have an estimated peak molecular weight (not including optional substituents) of at least 200,000, and at least part of the grafted polystyrene chains are functionalized with a chemical functionality which facilitates the formation of an anchoring linkage between the polystyrene moiety and an at least N-protected and optionally carboxyl terminal derivatized amino acid.
Very high loading with synthesized peptide can be achieved with a polystyrene-grafted polymer substrate as disclosed in WO 90/02749, and when in the preferred form of a sheet or film, such a polystyrene-grafted polymer substrate is particularly convenient for the purposes of parallel synthesis of multiple peptides. Thus, for example, it is easy to cut a sheet or film into pieces of any desired size and/or shape and to transfer such pieces, if appropriate, from one reaction vessel to another; furthermore, a material in the form of a sheet or film is easy to mark for identification purposes (e.g. in connection with the latter mentioned transfer between various reaction vessels).
Thus, when the invention disclosed in WO 90/02749 is employed in the context of parallel and substantially simultaneous synthesis of a plurality of peptides, an appropriate plurality of essentially identical substrates of the above-described type are provided, after which the synthesis proceeds as follows:
a) the members of the plurality of polystyrene-grafted polymer substrates are optionally physically segregated into two or more sets each comprising one or more members of the plurality; PA1 b) an N-protected and optionally carboxyl terminal derivatized amino acid is coupled to the functionalized polystyrene moieties of each member of the plurality or, where applicable, each member of each set, the N-protected and optionally carboxyl terminal derivatized amino acid employed being identical for all the members of the plurality or, where applicable, all the members of one set, and, where applicable, further being in accordance with one of the following alternatives: PA1 the functionality and the N-protected and optionally carboxyl terminal derivatized amino acid being adapted to each other such that the anchoring linkage formed can subsequently be cleaved substantially without degradation of the peptide or protein chain which is to be synthesized; PA1 c) each member of the plurality or, where applicable, each member of each set is treated so as to remove the N-protecting group from an N-protected amino or substituted amino group of the coupled and N-protected amino acid, such that reaction of the amino or substituted amino group of the coupled amino acid with a carboxyl group or an activated carboxyl group of a further N-protected amino acid is facilitated; PA1 d) the amino or substituted amino group of the amino acid last coupled to the functionalized polystyrene moieties of each member of the plurality or, where applicable, of each member of each set is reacted with a carboxyl group or an activated carboxyl group of a further N-protected amino acid, so as to form a peptide bond between the amino or substituted amino group and the carboxyl group or activated carboxyl group, the further N-protected amino acid being identical for all the members of the plurality or, where applicable, all the members of one set, and, where applicable, further being in accordance with one of the three alternatives mentioned above in connection with step b); PA1 e) each member of the plurality or, where applicable, each member of each set is optionally treated so as to remove the N-protecting group from an N-protected amino or substituted amino group of the last-coupled N-protected amino acid, such that reaction of the amino or substituted amino group of the latter amino acid with a carboxyl group or activated carboxyl group of a further N-protected amino acid is facilitated; PA1 f) in those cases where step e) has been performed, steps d) and e) are repeated a desired number of times; PA1 g) each member of the plurality or, where applicable, each member of each set is optionally treated so as to remove some or all protecting groups possibly remaining on the amino acid moieties of the synthesized peptide or protein chain; PA1 h) each member of the plurality or, where applicable, each member of each set is optionally treated so as to cleave the linkage anchoring the synthesized peptide or protein chain to the functionalized polystyrene moieties of each member of the plurality or, where applicable, of each member of each set; and, PA1 i) if appropriate, any further undesired group is removed from a synthesized peptide or protein chain. PA1 (i) still possesses excellent mechanical and optical properties, PA1 (ii) can withstand harsher chemical/physical conditions (e.g. higher temperatures, aggressive solvents) than the material of WO 90/02749, PA1 (iii) retains all the advantages of the material of WO 90/02749 with respect to, e.g., peptide synthesis, and PA1 (iv) can be further modified by functionalisation or derivatization with appropriate substituent groups so as to acquire a high degree of hydrophilicity while at the same time being compatible with synthetically relevant organic solvents and retaining good optical and mechanical properties.
(i) identical for all the sets, PA2 (ii) when the number of said sets is greater than two, identical for at least two of the sets, PA2 (iii) different for each set,
The methodology disclosed in WO 90/02749 is equally applicable to the synthesis of a single peptide or protein. In this case only one polystyrene-grafted polymer substrate of the type in question is used, and the alternatives mentioned under b) and f), above, do not then apply; apart from this, the steps in the process are entirely analogous to those recited above.
It is also appropriate to mention here another document, viz WO 91/13098. This document discloses solid supports which are very closely related to the polystyrene-grafted substrates of WO 90/02749 and which are suited for use in solid-phase biosystems, such as bioassays, e.g. immunoassays. The solid supports of WO 91/13098 differ from those of WO 90/02749 only in that they are functionalized with chemical functionalities from which a peptide which has been attached thereto, or a peptide which has been synthesized thereon (e.g. in the manner disclosed in WO 90/02749), will not become detached under any normally applying chemical or physical conditions.
After a number of years of experience in the handling and use of the inventions described in WO 90/02749 and WO 91/13098, it has become apparent that although the substrate/support materials disclosed therein offer a number of significant advantages in relation to the state of the known art at the time of filing of the respective PCT applications, it would nevertheless be advantageous to be able to improve the properties of the materials in certain respects.
Thus, for example, it became clear that the occlusion, in the PE film material, of polystyrene homopolymer during the grafting process led to undesirable inhomogeneity of the grafted material owing to the formation of small bubbles or blisters in the material. Apart from the fact that it is necessary to carry out a time-consuming extraction of this occluded homopolymer from the PS-grafted PE film in order to obtain a material with satisfactorily reproducible chemical and physical behaviour in the context of applications to synthesis, the inhomogeneity due to the above-mentioned bubbles/blisters results in the optical properties (e.g. clarity, light transmission and reflecting properties) of the PS-grafted PE-material being considerably poorer than could be desired.
It has also been found that, for example, at high levels of loading of synthesized peptide or protein on the PS-grafted PE substrates of WO 90/02749, the mechanical properties of the material deteriorate, leading to a tendency for the material to fragment in an uncontrolled fashion.
Furthermore, the thermal and other properties of the PS-grafted PE substrates of WO 90/02749 impose limits on the nature of the functionalities which can be introduced into the polystyrene part of the material, and on the conditions under which the materials in question can be used (thus, for example, the PS-grafted PE material of WO 90/02749 dissolves in solvents such as xylenes at 100.degree. C.). The ability to be able to withstand functionalisation conditions entailing, for example, the use of highly "aggressive" organic solvents (such as xylenes) and relatively high temperatures would permit functionalisation with a range of functionalities which could considerably broaden the synthetic applicability of the substrate material, and would therefore constitute a highly desirable improvement of the material.
Moreover, in continuing investigations of the applicability of the substrates disclosed in WO 91/13098 (vide supra) for use in solid-phase biosystems, such as bioassays, e.g. immunoassays, it became more and more clear that the lack of hydrophilicity of the material imposed limits on its breadth of applicability in connection with, for example, assays of the ELISA type. It thus became apparent that a material of the general type in question but having significantly improved hydrophilic properties would have considerable advantages.

Grafted cross-linked polyolefin substrates for peptide synthesis and assays


An air guard assembly used to direct air forced through an overhead air diffuser toward the floor of a building. The assembly has a plurality of elongated linear baffles. Each baffle has a strip of magnetic material that adheres directly to metal ceiling structures to surround and enclose the diffuser within the assembly. A gripping tool having an elongated handle is used to locate the baffle adjacent the metal ceiling surface and remove the baffle therefrom. The baffle has a pair of grooves preventing the gripping tool from slipping off the baffle.

Commonly, ceiling mounted air diffusing devices, called diffusers, are located adjacent the discharge ends of ventilation ducts in a building. These devices direct forced hot or cold air outwardly generally parallel to the ceiling surface. Panels of the ceiling located adjacent the diffusers often become soiled with sir born particulates, dust and dirt moving with the air flowing from the diffusers. Periodic cleaning and eventual replacement of the panels is required. Also, hot air flowing along the ceiling does not circulate downwardly to heat the space above the floor in a heat efficient manner.


A method of making a composite material consists of entraining finely divided solid additive particles in a stream of ionized inert gas and ionizing the inert gas and utilizing heat generated by the ionized gas to heat the solid particles to a high temperature which is less than the temperature in at which the solid particles become non-solid due to melting sublimination or dissociation. Then, injecting the stream of gas and entrained heated solid particles into a molten metal mass to provide a mixture of finely divided solid particles and molten metal and thereafter causing physical agitation of the mixture of molten metal and solid particles to establish a substantially uniform distribution of solid particles in the molten metal. Such physical agitation of molten metal is continued until the mixture of finely divided particles and metals is completely solidified.

Development of the aircraft and ship building, car making and a number of other industries require new materials having improved workability and service properties.
Metallic structural materials (alloys) are nowadays produced by melting the base metal to liquid form with additive components, with the melting process going at the temperature of the entire system which ensures the complete melting and mutual dissolution of the components (FIG. 2a).
With the drop of temperature of the alloy during cooling and solidification, the solubility of the alloy components sharply decreases and, at a certain temperature particular for each alloy system and composition, solid phases begin to precipitate and grow from the homogeneous melt in the form of alloy component crystals, or, more frequently, in the form of the crystals of the chemical compounds of components (intermetallic phases) (FIG. 2, b,c). With further cooling the rest of the melt is crystallized in the form of a solid solution of the components in the base metal (FIG. 2, d). Intermetallic phases with crystal lattice and properties different from those of the base alloy (matrix) strongly affect the properties of the alloy system as a whole.
The size of the intermetallic phases precipitated in the process of crystallization of the alloy should not exceed fractions of one micron, otherwise quality of the alloy will be sharply impaired due to loss of ductility and strength.
The solubility of metals and metalloids in the metallic matrix is very much limited in the solid state and this factor accounts for the narrow selection of commercial alloys and the practically achieved limit of improvement in the properties of the commercial structural alloys by change in composition.
A new class of structural materials have been developed, which contain artificially incorporated particles or fibers of oxides, carbides and other compounds enabling the attainment of assured properties of the system as a whole. Such materials are known as composites since the components of the metallic system are not precipitated from the matrix metal, as is the case with the conventional alloys, but are artificially incorporated into the system. All known metallic alloys representing the matrix with incorporated particles, whose properties significantly differ from the matrix, are basically the composites, although of natural occurrence in the making of the alloy.
The properties of metallic materials represented by a composite system of artificial or natural origin are indicated as follows:
ductility of the material is determined by ability of the matrix (as a rule the ability of the solid solutions of components in the base alloy) for plastic flow, as well as by size and syngonia (crystalline structure) of intermetalloid and other inclusions in the matrix); PA1 strength, heat resistance, fatigue strength, resistance of materials to development of cracks is determined by interaction of the of the inclusions and the matrix, as well as distortions of the crystalline lattice of the matrix under action of inclusions; PA1 hardness, wear resistance, tribotechnical properties of the material are determined by properties of the inclusions; PA1 modulus of elasticity, linear expansion factor, specific weight (density) of the material are determined by a set of properties of the matrix and inclusions. PA1 produotion of the basic melt; PA1 uniform distribution of solid particles in a mass molten metal; PA1 crystallization of the resultant composite material. PA1 mechanical stirring of the melt and added particles; PA1 pressing pellets mixed powered matrix metals and reinforcing particles followed by plunging the particles to the melt and mechanical stirring of the melt; PA1 dispersion of particles in melt by ultrasound irradiation. PA1 application of metal-philic coatings on the surface of the reinforcing filler particles; PA1 introduction of surfactants into the base metal melt; PA1 increase of the melt temperature.
Thus, the development of new metallic materials with a predetermined combination of workability and service properties should be theoretically achievable on the basis of selection of the optimum composition of the metallic system in each case, that is selection of the matrix and inclusions whose properties and interaction determine the properties of the composite system as a whole.
Selection of the metallic system base (matrix) is determined by required service properties of the material and level of its properties (steel, aluminum, copper, magnesium, nickel, etc.).
The major difficulty in implementation of the technology for production of structural metallic materials is the injection of components into the structure in the form of superfine particles of compounds thermodynamically and thermally stable in the matrix, and which measure from a few nanometres to a few microns.
In the production of natural composite metallic materials (i.e. complex alloys) this problem is dealt with by precipitation of particles (intermetalloids) from supersaturated solid solutions of the components of the alloy in the base metal produced by the use of high-rate cooling of homogeneous melts The required cooling rate can be practically achieved only in case of relatively small quantities of alloy melt In practice, a high cooling rate is provided by physical dispersion of the melt followed by cooling fine drops of the melt in a cooling medium This requires expensive operations of drying, degassing and compacting particles (granules) to provide pellets. Thus, the technology for production of new metallic alloys by the pelletizing technique has not found wide use in the industry.
The difficulty of introducing superfine particles into the metallic melts in attributed to two circumstances. First due to lack of fluidity of superfine particles (thousandths of microns or less in size) the metering of particles when injected into the melt is rather difficult or sometimes even impossible. Second, due to presence of adsorbed oxygen on the surface of the particles upon in contact with the melt, oxides of the base metal are formed on the surface, which prohibits wetting of the particles by the melt. This problem especially manifests itself during injection of the particles into the melts of metals having high oxygen reactivity (aluminum, magnesium, etc.). The above factor also inhibits implementation of such techniques as the direct modification of the alloys by injection of particles--crystallization nuclei into the melt, alloying the melts by injection of alloy components in the form of the powder, use of powdered waste of alloying materials (e.g. silicon) in production of alloys, in particular those of aluminum-silicon system.
One of the most important features of the proposed technology and devices for its implementation is the possibility of injection into the melt of fine particles of the filler materials (in case of production of composites) or structural components (in case of production of alloys), with the formation of the alloy structure following the scheme shown in FIG. 2A.
The matrix free from the atoms of the component is injected with particles of a desired filler material (FIG. 3a). When equilibrium of the system exists between the structural component (Ax By) and solution of the alloy component B in the matrix A, particles incorporated into the matrix dissolve to the concentration of saturation at the appropriate temperature with the decrease in size, this process is highly controllable and enables production of alloys with structure with alloy a predetermined component of limited solubility.
Major stages of a process for the production of cast composite materials involved are described in "Solidification, Structures and Properties of Cast Metal-Ceramic Particle Composites"--Rohatgi P. K., Asthana R., Das S.--Inst. Metal Rev.,--1986--Vol. 31, N3--pp. 15-139 and include:
The following methods have been used in the prior art for injection of superfine particles into a melt as described in "Cast Aluminum-Graphite Particle Composites--a Potential Engineering Material"--Rohatgi P. K., Das S., Dan T. K.--J. Inst. Eng.,--March, 1989--Vol. 67, N2--pp. 77-83:
Problems encountered in the production of cast metal composites relate to lack of or low wetability of the reinforcing filler particles with the matrix melt, as well as non-uniformity of the cast material due to large differences in densities between the matrix and the filler material.
Increase in the strength of the bond between the reinforcing filler particles and the base metal matrix is achieved by a number of techniques as described in "Wetability of Graphite to Liquid Aluminum and the Effect of alloying Elements on It", Choh Takao, Kemmel Roland, Oki Takeo--Z. Metallklunde"--1987--Vol. 78, N4--pp. 286-290, i.e.:
There is also known a method for production of composites (Application No. 56-141960, Japan, dated Aug. 4, 1980 (No. 55-45955), published May 11, 1981) in which is suggested the use as a filler of natural hollow microspheres 150 micron in diameter sufficiently compatible with various metallic materials, as well as graphite powders, TiB.sub.2, aluminum nitride and oxide, flaky and chipped graphite and calcium metal is added to the melt in quantity of 0.05-5.0 wt. % to ensure uniformity of materials.
The major disadvantage of this method is the necessity for introduction into the melt of an element (calcium) which is soluble in the liquid base metal, but practically insoluble in the case solid matrix and which forms a brittle eutectic component with the matrix. This results in lowered mechanical properties of the matrix and of the composite itself. Besides, the use, as a filler, of hollow microspheres of the recited sizes (150 micron) does not help to improve absolute values of mechanical properties and can result only in some improvement in their relative values per unit of mass.
Prior art relevant to the present invention is the method for production of composite materials (Met. Trans., 1978, v. 9 N 3, pp. 383-388) using the base molten metals--Mg. Al, Fe, Ni, Cr, Co doped with insoluble oxide particles (Al.sub.2 O.sub.3, BeO, CaO, CeO.sub.2, TiO.sub.2, MgO, ThO.sub.2, VO.sub.2, ZrO.sub.2), carbides, borides, nitrides of Nb, Ta, Hf, Ti, Zr sized 0.01-10 micron. The particles are injected as powder or thin fibers To ensure uniform distribution of the particles in the melt they are injected in a stream of preheated inert gas (Ar, He) while vigorously stirring the base metal. Volume percentage of particles may range from 0.5 to 20%. Also one of the elements which improve the surface activity at the interface the particle-melt is injected into the molten metal. Injection of such surface active metals (Mg, Si, Ti, Zr, V, Nb) ensures formation of a metalphilic casing on the oxides which significantly improves wetability in the system and there is no segregation in the melt over a period of 30 min.
The foregoing method has the following disadvantages:
1) the chemical composition of the matrix melt is limited by need to inject surface active metals which in a number of cases may lead to impairment of technological and mechanical properties of the resulting composite material;
2) the absence of stirring in the course of solidification promotes, especially in case of a long solidification time, the formation of segregated and laminated areas, and consequently quality of the resulting composite material is lowered;
3) insolubility of the reinforcing particles excludes the possibility of using this method for production of materials with the matrix reinforced with superfine particles of those elements or their compounds which are traditional strengtheners in production of materials by joint crystallization of the base metal with alloying additives and subsequent thermo-mechanical working.

Method for production of metal base composite material

Vsesojuzny Nauchno-Issledovatelysky I Proektny Institut Aluminievoi, Magnievoi I Elektrodnoi Promyshlennosti


In a method and an apparatus for recovering a sterilizing gas, in particular ethylene oxide (ETO), materials to be sterilized are sterilized in a sterilizing chamber with a sterilizing gas and a gas flow is withdrawn from the sterilizing chamber. At least part of the sterilizing gas contained in said gas flow is liquefied and separated. The gas flow freed from liquefied sterilizing gas is returned to the sterilizing chamber whilst at the same time at least a part of the separated sterilizing gas is replaced by addition of inert-rendering gas, reducing the concentration of the sterilizing gas in the sterilizing chamber.

1. Field of the Invention
The invention relates to a method and apparatus for recovering a sterilizing gas, in particular ethylene oxide, in which materials to be sterilized are sterilized in a sterilizing chamber with a sterilizing gas. A gas flow is withdrawn from the sterilizing chamber and at least a part of the sterilizing gas contained therein is separated from the gas flow.
2. Description of the Prior Art
Usually, alkylene oxides, in particular ethylene oxide, are used as sterilizing gases which are generally mixed with gases which render them inert, such as Freon (dichlorodifluoromethane) or inert gases, in particular nitrogen. For costs and environmental reasons the sterilizing gas mixtures, i.e. the actual sterilizing gas and the other constituents rendering them inert, are not simply released into the environment after a sterilizing operation but are recovered and used again.
Thus, US-PS 3,549,312 discloses a method and an apparatus for recovering alkylene oxide and the admixed inert constituents in which the mixture of alkylene oxide and the inert additives extracted from a sterilizing chamber are supplied to a precooler and subsequently to an absorber. The mixture freed from moisture in the absorber then passes to a condenser for liquefaction of the alkylene oxide and the admixed Freon R 12 and thereafter to a reservoir for intermediate storage of the liquid mixture. This mixture can finally be supplied to the sterilizing chamber again from the reservoir subjected to excess pressure. A disadvantage with this recovery method is that the sterilizing chamber is pumped out after a sterilizing cycle in order to supply the gas or gas mixture to the connected recovery section of the apparatus and to be able to use it in the following sterilizing cycle. In a recovery method according to U.S. Pat. No. 3,549,312 during the pumping of the sterilizing gas or the gas mixture, simultaneously ambient air is allowed into the sterilizing chamber. Although the admitted air and the sterilizing gas or gas mixture to be pumped off have large density differences and thus remain separate from each other in a natural manner, there is a possibility, that in particular towards the end of the pumping operation to an increasing extent in and undesirable manner ambient air gets into the recovery apparatus. This danger is present precisely because the sterilizing chamber must be pumped down to small sterilizing gas residues in order to be able to open said chamber thereafter for the next sterilizing cycle.
According to a method disclosed in EP-A 0 130 319 for purifying ethylene oxide or a mixture of ethylene oxide and a fluorinated hydrocarbon, the sterilizing chamber subjected to excess pressure during the sterilizing is first relieved of pressure after each sterilizing process and thereafter evacuated with an oil-free operating vacuum pump down to a pressure of between 10 and 100 mbar. The discharged and thereafter extracted gases are purified and recovered in order to be made available for a new sterilizing operation. This remaining evacuation down to at least 100 mbar is intended to keep the loss of sterilizing gas down to an acceptable level. In an apparatus operating by this method, within the recovery section of the sterilizing apparatus, complicated pump and cooling systems are necessary for evacuating the sterilizing chamber. Furthermore, during the recovery itself, the pressure in the components and conduit systems of the recovery section changes continuously from the initial pressure in the chamber, lying above atmospheric pressure, down to the pressure of 10 to 100 mbar.
A method and an apparatus for recovery of a sterilizing gas, according to which after a sterilizing process the sterilizing gas is likewise pumped out of the sterilizing chamber and recovered in a recovery cycle is disclosed in German patent application no. 41 17 306.6, which was not previously published.
A further method and an apparatus for recovery of at least one component of a sterilizing gas is disclosed in EP-A-0 326 985. To discharge the gas mixture from the sterilizing chamber, it is proposed in the case of a chamber pressure lying close to atmospheric pressure to force a gas, for example nitrogen, at a higher pressure into the sterilizing chamber and thereby expel the sterilizing gas. The chamber pressure here will lie at least at times above the atmospheric pressure, thereby increasing the danger of leakage losses, i.e. escape of toxic sterilizing gas to the environment. Another disadvantage is the high nitrogen consumption on expelling the sterilizing gas.
Furthermore, it is known from EP-A-0 417 592, in the recovery of solvents collecting in continuously conducted production processes, for example on drying coated video and audio tapes, to fill the dryer with an inert gas and to recover the solvent vapours arising during drying together with said inert gas in a solvent recovery cycle and to return the gas freed from solvent vapours to the dryer again. In a removable apparatus for such a solvent recovery plant as apparent from German patent application P 40 40 389, which was not previously published, mixture can be withdrawn and simultaneously pure inert gas supplied to the dryer not only via the solvent cycle but also via an additional exit and inlet conduit. The objective of this is to enable the gas atmosphere of the dryer to be brought within a very short time to normal values again or maintained within the admissible values in the event of trouble in the dryer.


A method comprises positioning a pair of photovoltaic wafers in a side-by-side arrangement. An interconnect is placed on the pair of wafers such that the interconnect overlaps both wafers of the pair, solder material being provided between the interconnect and the respective wafers. A solder head is then located adjacent the interconnect, and the coil is energized to effect inductive heating of the solder material. The solder head comprises an induction coil shaped to define an eye, and a magnetic field concentrator located at least partially in the eye of the coil. The magnetic field concentrator defines a passage extending axially through the eye of the coil, and may be of a material with a high magnetic permeability.

Photovoltaic systems, which serve to convert solar energy to electrical energy, often include solar panels comprised of multiple photovoltaic wafers which are electrically connected. Such electrical connection of adjacent or neighbouring wafers in a panel may be provided by a metal connector or interconnect, which is connected by soldering to electrical contacts on the respective wafers.
The soldering connection of the interconnect to a pair of wafers may be performed by induction soldering, in which an induction coil is positioned proximate a contact that is to be soldered to the interconnect. A magnetic field is then generated by the coil due to electrical current passing through the coil, the coil being positioned such that solder material located between the interconnect and the electrical contact melts because of inductive heating of the interconnect and the solder material by the magnetic field.

Induction soldering of photovoltaic system components


Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a self-learning robotic process automation are disclosed. In one aspect, a method includes receiving an automated script that includes one or more commands and that is configured to interact with graphical elements that appear on a user interface. The method further includes executing a command of the one or more commands of the automated script. The method further includes determining that an error occurred during execution of the command of the one or more commands of the automated script. The method further includes determining a modification for the command by applying a script repair model. The method further includes executing the modified command. The method further includes determining whether the error or another error occurred during execution of the modified command. The method further includes determining whether to update the automated script with the modified command.

Manual processes performed on a computer may be repetitive and time consuming. For example, a user may send e-mails in response to web form submissions, and for each web form submission, may need to manually interact with a computer to click buttons to open a window for composing a new e-mail, click buttons to copy information from the web form submission into the window, click keys to write text for a body of the e-mail, and click buttons to send the e-mail.

This patent is subject to a terminal disclaimer.

Self-learning robotic process automation


Groups of DCVS (Differential Cascode Voltage Switch) circuits are interconnected by single-track data transfer connections. Each group contains one or more DCVS tree circuits, through which data signals propagate only on dual-track connections. In each group, at least one DCVS tree circuit is configured as an input boundary tree, and at least one tree circuit is configured as an output boundary tree. All data inputs externally applied to a group, are transferred only through input boundary trees of the group, and all data outputs transferred out of a group leave the group only through output boundary trees of the group. If a group has only a single tree, that tree serves as input and output boundary tree of the group. Each input boundary tree of each group has one or more associated primary shift register latch (SRL) circuits through which all external data inputs to that tree are transferred. Such external data inputs are received through the single-track connections mentioned above. The primary SRL circuits are also used to present predeterminable test data inputs to respective trees, and to collect primary test data outputs representing signals received through the single-track connections. In such usage, the SRL circuits are connected as a scannable shift register. Each output boundary tree has an exclusive-OR (XOR) circuit for indicating if the respective tree is in a legal or illegal state. The XOR circuits connect to secondary scannable SRL circuits for external presentation of illegal state indication. The primary test data outputs together with the externally presented illegal state indications form a basis for detecting and locating any faulty state in any group.

DCVS (Differential Cascode Voltage Switch) circuits, developed for VLSI applications, are capable of providing high functional density and performance. Such circuits comprise "tree" clusters of active device pairs which operate as discrete logic circuits. Each tree receives complementary input signals on pairs of conductors, and produces an output signal having a predetermined logical relation to the input signals. The output signal, presented on a pair of conductors, is in a "legal" state only if the signals on the respective conductors are at different levels, and in an "illegal" state otherwise.
Presently, the paired conductors on which input and output signals are conveyed relative to trees are termed "2-track" or "dual-track" connections". Dual-track connections consume more chip space and are more difficult to route through a chip than single-track (single wire) connections. However, single-track connections have not been considered feasible because they permit propagation of faulty signals between trees with essentially indeterminate effects.
It is also desirable to be able to test integrated logic circuits on a chip, including DCVS tree circuits. A simple presently well known testing technique involves arranging circuits to be tested in "level sensitive scan design" (LSSD) groups, and providing "scannable shift register latch" (SRL) circuits integral with each group. Test signals scanned into the SRL latches are applied to respective groups, the groups are operated for a clock cycle during which signals representing states of groups are scanned into SRL circuits (usually of other groups), and the signals then stored in the SRL circuits are scanned out for evaluation (fault detection and location) either off chip or on chip. The LSSD grouping is supposed to ensure that any fault conditions in a group can be detected and traced by one or more scan in/scan out operations.
Arrangements of this kind and their rationale are presented in "A Logic Design Structure For LSI Testability", E. B. Eichelberger et al, Proceedings of the 14th Design Automation Conference (1977), IEEE, pages 206-215 (hereafter referred to as the "Eichelberger paper").
It has been proposed also to use scannable shift register latches to facilitate testing of DCVS circuits. Refer, for instance, to U.S. Pat. Nos. 4,698,830 and 4,656,417, and IBM Technical Disclosure Bulletin, Vol. 27, No. 10B, pages 6148-6152, J. B. Hickson et al, "Testing Scheme For Differential Cascode Voltage Switch Circuits. However, these proposals have a number of shortcomings in that their implementations would require departure from existing (and proven) LSSD design practices, and not alleviate the previously stated use of 2-track connections between DCVS circuit groups.
Accordingly, the aim of this invention is to provide an arrangement of DCVS circuits which allows for routing of signals between DCVS circuits over single-track connections (hereafter also termed single-track global interconnect wiring), while permitting complete and accurate testing such that all faults including illegal output states of DCVS tree circuits are detectable and traceable.

Fully testable DCVS circuits with single-track global wiring


A process of preparing a compound of the formula (I)

Compounds which are potent inhibitors of purine nucleoside phosphorylase and are useful for suppressing T-cell function and/or treating and/or preventing infections caused by protozoan parasites are described in Biochemistry, 1998, 37, 8615-8621 and in our co-pending PCT International Patent Application No. PCT/US98/21717 (WO 99/19338).
There remains a need for alternate, simpler methods of preparing these compounds.
It is therefore an object of the present invention to provide an alternate process for preparing these compounds, which will at least provide the public with a useful choice.

Process for preparing inhibitors of nucleoside metabolism

Abstract: wherein B is chosen from OH, NH2, NHR, H or halogen; D is chosen from OH, NH2, NHR, H halogen or SCH3; R is an optionally substituted alkyl, aralkyl or aryl group; and Z is selected from OH, hydrogen, halogen, hydroxy, SQ or OQ, Q is an optionally substituted alkyl, aralkyl or aryl group; or a tautomer thereof; or a pharmaceutically acceptable salt thereof; or an ester thereof; or a prodrug thereof,which comprises reacting a compound of the formula (II)

Abstract: with an anion produced by abstraction of the bromine or iodine atom from a compound of formula (XIX),

Abstract: to form a compound of formula (XX)

Abstract: The compound of formula (XX) is N- and O-deprotected to obtain the compound of formula (I).

Albert Einstein College of Medicine of Yeshiva University


Structural testing can lead to high and abnormal current surges. Disclosed herein are methods for designing and testing an IC so that current surges therein may be minimized while the IC is being tested. One disclosed way to minimize current surges is by gating out shift induced node state transitions. Another disclosed way to minimize current surges is to operate two or more of an IC's scan chains in parallel, but out-of-phase.

Prior to shipping an IC to an end user, the IC must be tested to determine whether it has been manufactured correctly and is fully operational. A variety of IC testers are available for such testing. Typically, an IC tester is a very large and expensive machine which is designed to precisely position the placement of logic signal transitions at very high speeds. Most testers are aimed at creating a "functional environment" for an IC. A functional environment is one which mimics the environment in which the IC will eventually be used, to thereby demonstrate that the IC will behave as expected in that environment. A tester which creates a functional environment for an IC is referred to as a "functional" tester.
A functional tester applies a series of "test vectors" to the inputs of an IC. A test vector is a critically timed cycle of events lasting a short period of time referred to as a "vector cycle". Within a vector cycle, and at precisely calculated times, logic signal drivers in the tester apply stimulus to IC inputs. At the same or some precisely delayed time, logic signal comparators in the tester monitor responses at IC outputs. When many test vectors are executed sequentially, discrepancies between monitored and expected IC outputs, if any, are noted as IC failures. Failed ICs are then scrapped, and passed ICs are shipped to customers.
A vector cycle may last only a few nanoseconds, and a plurality of events may be timed within the cycle, with each event having a resolution in time as short as ten picoseconds. As technology continues to advance, there are increasing pressures for even shorter cycle times and finer event resolution. To complicate matters even more, functional tests are very difficult to prepare and may suffer from unknown fault coverage (i.e., unknown quality). Typically, functional tests for an IC must be created by those who designed the IC, and little automation can be used in the creation of the tests. While simulators can be used to predict how an IC will behave, simulators are often not the solution because 1) simulators often have limited fault modeling capability and, as a result, have a limited ability to determine how a test will react to "real world" faults, and 2) simulation is expensive and time-consuming, especially when generated tests are of an unknown quality.
An alternative or adjunct to functional testing is "structural" testing. Structural testing became of interest in the mid-1970's, and is discussed in detail in the paper of M. J. Y. Williams and J. B. Angell entitled "Enhancing Testability of Large-Scale Integrated Circuits Via Test Points and Additional Logic", IEEE Trans. on Computers, vol. C-22, no. 1 pp. 46–60 (January, 1973), and in the paper of E. B. Eichelberger and T. W. Williams entitled "A Logic Design Structure for LSI Testability", Proc. 14th Design Automation Conf., IEEE Pub. 77CH1216-1C, pp. 462–468 (June, 1977), which papers are hereby incorporated by reference for all that they disclose. Initially called "scan" testing, structural testing enables the testing of structures which are deeply embedded within an IC. Rather than testing the IC's internal structure by applying stimulus to the IC's inputs, structural testing involves shifting a series of test vectors into the core of an IC, and after each test vector is shifted in, launching the test vector and capturing a response. Each response is then shifted out of the IC. In this manner, a tester can verify that all of an IC's elements are present and operational. An assumption of structural testing is that if all elements are present and operational, then the elements will contribute to performing the greater and intended functions of an IC (e.g., adding, shifting, etc.), and the IC will function as designed.
FIGS. 6 and 13 illustrate conventional ICs which incorporate one or more scan chains for the purpose of enabling structural testing of the ICs. An IC which is designed for structural testing is commonly referred to as being "designed for test", and therefore incorporates "design for test" (DFT) structures. The basic rules (i.e., DFT rules) for enabling structural testing of an IC are:                1. Implement the IC using synchronous clocked design (no asynchronous feedback).        2. In place of each register element (e.g., flip-flops) in the IC, insert a more complicated register element (i.e., a scan chain cell) having two modes of operation:                    a. A "normal mode" where the element works as a clocked memory element as required for the functionality of the IC; and            b. A "test mode" where the element behaves as a member of a scan chain (i.e., a serial shift register chain).                        3. Link the scan chain cells to form a scan chain and route appropriate signals (e.g., mode, shift and data I/O signals) to each of the cells.
If desired, structural testing can be expanded to the board level. When designing a board, a designer can link signals of each IC at the board level (e.g., mode, shift and data I/O signals) to thereby expand structural testing to the board test level. A detailed discussion of various scan chains may be found in the paper of T. W. Williams and K. P. Parker entitled "Design for Testability—A Survey", Proceedings of the IEEE, (Invited paper), vol. 71, no. 1, pp. 98–112 (January, 1983).
Once an IC has been made scan-testable, then its structure becomes logically equivalent to a combinational logic network surrounded by a rank of memory elements (i.e., the scan chain). Since test vectors can be shifted into and out of the memory elements of a scan chain, the elements become test resources that can 1) supply inputs to the combinational logic network, and/or 2) monitor outputs of the combinational logic network. Thus, the essentially intractable test generation problem for a sequential digital circuit of arbitrary complexity is reduced to the much simpler test generation problem for a combinational circuit, for which much automated technology exists.
Tests for a combinational circuit may be generated by an Automated Test Program Generator (ATPG) which is given the circuit description and a list of faults to be tested. Since an ATPG is typically designed to generate parallel test vectors (i.e., test vectors which can be applied to and received from the inputs and outputs of a combinational circuit), a serializer algorithm can be provided with both the parallel test vectors, and a description of the combinational circuit and scan chain, to thereby create a serial test program that can deliver the parallel test vector inputs to the combinational circuit via the scan chain. When a parallel test vector is in place, a normal clock pattern of the combinational circuit is then triggered for the purpose of launching the test vector into the combinational circuit. Finally, a response to the test vector is collected in elements of the scan chain and shifted out of the scan chain serially.

Methods and apparatus for minimizing current surges during integrated circuit testing


A light-emitting device includes a number of light-emitting element groups each including a plurality of light-emitting elements, a first drive device for driving the plurality of light-emitting elements in succession, and a number of resistance sections, each separately connected to each of the light-emitting element groups. The resistance section is connected in common to the plurality of light-emitting elements. The light-emitting device further includes a second drive device for driving the light-emitting element groups.

1. Field of the Invention
This invention relates to a light-emitting device, and particularly to a light-emitting device suitable for use in an image forming apparatus such as a copying apparatus, a facsimile apparatus or a printer.
2. Related Background Art
An LED recording head is comprised of a number of LED chips and a drive IC for driving them linearly mounted on a substrate, and when it is used, for example, in a copying apparatus, light is applied from an LED element onto a photosensitive drum to thereby form a latent image.
FIGS. 1A and 1B of the accompanying drawings are a schematic circuit diagram and a cross-sectional view, respectively, showing the construction of an LED head accord ing to the prior art. LED elements 1-1, 1-2, . . . , 1-5 linearly arranged in an LED chip 1 are connected to transistors 4-1, 4-2, . . . , 4-5 in a drive IC 10 in one-to-one relationship by bonding wires 2-1, 2-2, . . . , 2-5. Limiting resistances 3-1, 3-2, 3-5 prescribe electric currents for driving the LED elements 1-1, 1-2, . . . , 1-5 they take under their charge. In the drive IC 10, there are provided the limiting resistances 3-1, 3-2, . . . , 3-5, the transistors 4-1, 4-2, . . . , 4-5 and a control section 5. The LED chip 1 and the drive IC 10 are disposed on one and the same substrate 6.
Now, it is known that an LED is generally reduced by about 1% in its light emission intensity for a one-degree rise of environmental temperature, and to effect image reproduction of high quality, it is important to suppress a temperature rise including that of the drive IC 10. When the fluctuation of this output is great, the application is limited to only binary recording.
In the prior-art LED recording head of FIGS. 1A and 1B, generally the limiting resistances 3-1, 3-2, . . . , 3-5 substantially determine the temperature rise of the drive IC 10 including the control section 5. Heat generated by these limiting resistances is transmitted to the LED elements via the bonding wires 2, thus resulting in a reduced light emission output.
The limiting resistances are once dropped onto the substrate by the bonding wires and further are connected from the substrate to the LED chip by the bonding wires, whereby the heat is discharged to the substrate and the heat conducting action is alleviated, but the number of bonding wires becomes double, and when a recording head of high resolution and great length is to be realized, it is unrealistic in terms of cost.
Also, to place only these limiting resistances out of the drive IC 10 and dispose them at a location thermally remote from the LED chip 1, thousands of chip resistances must be mounted discretely from the drive IC and thus, the substrate itself becomes bulky, and this also is unrealistic.

Light-emitting device and image forming apparatus using the same


The present invention provides an apparatus for noninvasive determination of bone mass, said apparatus having a platform for supporting a bone to be measured, a spring having a selected stiffness which connects the platform to a sensor capable of measuring vibration velocity and force, and a vibrating means connected to the sensor, wherein the vibrating means exposes the sensor, the spring and the platform to vibration so that vibration velocity and force can be measured by the sensor and the mass of the bone determined. A second apparatus for noninvasive determination of bone mass having a gripping means, a spring having a selected stiffness which connects the gripping means to a platform for positioning of a bone, a sensor capable of measuring vibration velocity and force which connects the platform to a vibrating means, and a vibrating means which vibrates the sensor, the platform, the spring, and the gripping means so the vibration velocity and force can be measured by the sensor is also provided. In addition, a method of noninvasively determining mass of a bone with these apparatuses is provided.

Existing techniques for bone quality assessment are based on photon and X-ray absorptiometry and X-ray quantitative computed tomography. Gramp et al. The Radiological Clinics of North America 1993 31(5):1133-1141; Faulkner et al. Am. J. Roentgenology 1991 157:1229-1237. Each of these methods are routinely used in clinical practice. However, these techniques have limited applicability because of expensive and bulky equipment and potential risk of radiation during the procedure.
The application of acoustic energy for non-invasive skeletal diagnosis has also been shown to be feasible and has advantages for bone mass and strength measurement. Jurist, J. Phys. Med. Biol. 1970 15:417-426; Orne, D. Biomechanics 1974 7:249-257; Thomson et al. Med. Biol. Eng. 1976 14:253-262; Saha, S. and Lakes, R. S., J. Biomechan. 1977 10:393-401; Doherty et al. J. Biomechan. 1974 7:559-561; Waud et al. Calcif. Tissue Int. 1992 51:415-418; Selle, W. A. and Jurist, J. M. J. Am. Geriat. Soc. 1966b 14:930. Unlike conventional radiological techniques, acoustic techniques emit no radiation, are cost effective, and utilize equipment which is portable and easy to operate. Subsonic techniques for determining the in vivo properties of bone, known as impedance and resonance methods are based on measurement of the response of a bone to a flexural wave excitation in the frequency range 200 to 1000 Hz. A correlation between the resonance frequency of the human ulna and osteoporosis has been reported. However, while a significant number of acoustic tests have been performed, these techniques have not been used as a bone diagnostic tool for clinical application because of difficulties in the interpretation of the measurements. Ultrasound velocity and attenuation depend on density as well as on certain other properties of bone. A recent report showed that only 53% of broadband ultrasound attenuation (BUA) value and 44% of velocity of sound (VOS) value can be accounted for by bone density. Waud et al. Calcif. Tissue Int. 1992 51:415-418. Interpretation of subsonic measurement of flexural vibration of bone is also a difficult task and to a great extent, depends upon a corresponding mathematical model of the test object. The effect of soft tissues creates additional difficulties in the interpretation and use of these techniques.
A non-invasive, nonhazardous and cost effective infrasound resonance method for the quantitative measurement and monitoring of bone quality has now been developed involving the measurement of the rigid body longitudinal resonance of a bone. Instrumentation for making these measurements is also provided.

Non-invasive technique for bone mass measurement

The Trustees of Stevens Institute of Technology


Land-based vehicle including an arrangement for monitoring objects in or about a vehicle which includes a source from which illumination is emitted into an area in or about the vehicle, a receiver arranged to receive illumination reflected from an object in the path of the illumination, a light-regulating component arranged in front of the receiver to regulate reception of illumination by the receiver, and circuitry coupled to the source, the receiver and the light-regulating component. The light-regulating component is modulated to enable a determination of a distance between an object from which the illumination has been reflected and the receiver. The circuitry obtains information about objects from which the received illumination has been reflected other than distance information and associates with the objects distances between the objects and the receiver. This improves the ability to control vehicular systems based on the presence of objects in or about the vehicle.

A detailed background of the invention is found in a parent application, U.S. patent application Ser. No. 10/413,426, incorporated by reference herein, in particular in section 4.4.
The definitions in the Background of the Invention section of a parent application, U.S. patent application Ser. No. 11/025,501 are also incorporated by reference herein.

Vehicle-mounted monitoring arrangement and method using light-regulation

Automotive Technologies International, Inc.


In a cigarette packet appearing essentially as a parallelepiped body capable of accommodating at least two groups of cigarettes enveloped in respective wrappers surrounded by at least one internal collar, the body and wrappers each exhibit a front face, a rear face and two flank faces; the individually wrapped groups of cigarettes are positioned one adjacent to the other with the relative wrappers in mutual contact by way of the broader front and rear faces rather than by way of the flanks.

The present invention relates to a packet of cigarettes.
The invention relates in particular to a rigid type of cigarette packet with a flip-top hinged lid, but is also applicable to the soft, crush type packets. Cigarette packets currently in use include a type embodied in such a way as to accommodate two distinct internal wrappers, each enveloping a respective group of cigarettes, disposed one beside the other and in mutual contact along two flanks, that is, offering one of two narrower faces one to another. The packets in question exhibit a flat, elongated configuration, and more exactly, a relatively small lesser dimension or depth (generally corresponding to the depth of a double layer of cigarettes), and a relatively large greater dimension, or breadth. Clearly, when filled with an appreciable number of cigarettes, i.e. a number greater than 20 or 25, the breadth dimension of packets embodied in this way tends to take on proportions, commensurate with the depth of the groups of cigarettes, that lead to difficulties in manufacture when using conventional packaging machines to and to problems with use.
The object of the present invention is to provide a packet of cigarettes unaffected by the drawbacks mentioned above.


In-situ upgrading of heavy hydrocarbons includes injecting into a reservoir solvent, an asphaltene precipitant additive and optionally steam, at a ratio of solvent to heavy hydrocarbon between 0.1:1 and 20:1 under reservoir conditions. The additive has C—H, C—C and/or C—O bonds that thermally crack to generate free radicals in the vapor phase after injection. Formed downhole are a blend containing an upgraded hydrocarbon, and precipitated asphaltenes. The upgraded hydrocarbon is produced such that the precipitated asphaltenes remain in the reservoir. The upgraded hydrocarbon has a greater API gravity, lower asphaltene content, and lower viscosity than the heavy hydrocarbon. The precipitated asphaltenes are present in a higher amount than a similar blend not containing the additive. A method for selecting the additive includes identifying candidate additives having bonds that crack to generate free radicals in the vapor phase at the operating temperature, and calculating percent increase of asphaltenes precipitated for each.

Subsurface upgrading of heavy oil (HO) has been of interest to the petroleum industry because of the intrinsic advantages compared with aboveground counterparts. The main advantages are lower lifting and transportation costs from the underground to the refining centers with the potential increase of the volumetric production rate of wells and in the value of the upgraded oil, decrease in consumption of costly light and medium petroleum oils used as solvents for HO production, move estimated and probable HO reserves to proved reserves, possibility of reducing capital and operating expenses of upgrader units by performing the upgrading subsurface and use of porous media (a mineral formation) as a natural chemical "catalytic reactor" to further improve the properties of upgraded crude oil. However, there are significant challenges that must be addressed to accomplish a successful downhole upgrading process.
Several methods have been proposed for producing such heavy hydrocarbons. These methods include the use of multiple wells including parallel horizontal wells drilled into water formations beneath the heavy hydrocarbon, and injection of various additives through the horizontal wells to assist in production from a separate well drilled into the producing formation. Unfortunately, this method requires the actual drilling of a potentially large number of wells for production from a single well, with the attendant increase in cost of labor and equipment, and results in large amounts of potentially expensive additives being injected through the horizontal wells.
"Huff and puff" or cyclic pressurizing and production techniques are also known wherein a well is pressurized for a period, and then allowed to produce. This method can provide some enhanced production for certain wells. However, with particularly heavy hydrocarbons, this technique leaves much room for improvement.
In SPE paper No. 25452, a process for the in-situ upgrading of heavy oils and bitumen by propane deasphalting is proposed. This process utilizes two parallel horizontal wells, as reported in the Steam Assisted Gravity Drainage process (SAGD), but with the steam chamber being replaced by a chamber containing hydrocarbon vapor near its dew point. In this process, cold propane is continuously injected for the top horizontal well and the upgraded heavy oil/solvent blend is produced from the bottom well. The heavy oil is upgraded in terms of permanent viscosity reduction via solvent deasphalting.
Gupta and Gittins (Conference paper No. 2005-190 presented at Canadian International Petroleum Conference, Jun. 7-9, 2005, Calgary, Alberta) reported the field testing of a solvent aided process which involves the co-injection of a hydrocarbon solvent and steam during SAGD operation. The authors observed increases up to one degree of the API gravity of the produced oil.
In U.S. Pat. No. 6,883,607, a process for the recovery of hydrocarbons is disclosed which involves the use of warm solvents to extract heavy oil from oil bearing formation. The solvent is continuously injected downhole and placed into the formation at a temperature and pressure sufficient for the solvent to be in the vapor state and to condense on the extraction surface. Then, a solvent-heavy oil blend is produced and, after solvent separation and purification, it is re-injected into the formation again. The patent further discloses that the presence of the solvent in the heavy oil leads to precipitation of asphaltenes which upgrades the heavy oil via improvements in the API and reduction of metals and sulfur contents and Conradson carbon.
Another example is U.S. Pat. No. 6,405,799 which discloses a process for in situ upgrading of a heavy hydrocarbon. The process includes the steps of (a) positioning a well in a reservoir containing a heavy hydrocarbon having an initial API gravity of less than or equal to about 8; (b) injecting a light solvent into the well at reservoir conditions to provide an upgraded hydrocarbon in the reservoir, the upgraded hydrocarbon having an improved API gravity greater than the initial API gravity; and (c) producing the upgraded hydrocarbon from the well.
In the above mentioned prior art, the use of large amounts of solvent is required to precipitate asphaltenes downhole to upgrade of the heavy oil, as measured by, for example, API gravity increase and permanent viscosity reduction. Independent of the type of process, for example, huff and puff (discontinuous) or continuous solvent injection such as used in a variation of SAGD, the solvent to produced-heavy oil ratios used in the field are in the range of from about 0.5 to about 10 volume per volume (v/v). These high solvent-to-heavy-oil ratios not only increase the operating expenses of the process due to the need of high solvent inventories but also increase the capital costs due to larger size surface facilities for solvent separation, purification and recycling. Additionally, due to loss of injected solvent to thief zones present in the reservoir, there is a need for solvent make-up that further increases the operating costs of the downhole upgrading processes.
As an alternative to the above techniques, to reduce the solvent-to-oil ratio (SvOR) and to generate cost savings, U.S. Pat. No. 9,670,760 discloses the use of benzoyl peroxide (BP), 4-vinyl pyridine methacrylate, 4-vinyl phenol methacrylate, poly(maleic anhydride), iron and nickel nanoparticles as asphaltene precipitants for heavy crude oils. Initial experiments showed that BP provided an increase of ˜21 wt. % in the asphaltene content for a 2500 ppm dosage and 50° C. These results indicated that, at the same SvOR, adding in small amounts (ppm) of an asphaltene precipitant can increase the API gravity of the produced oil by 5.4° API and increase the amount of asphaltenes precipitated by almost 5 wt. %. These results indicated that it is possible to save between 30 to 50 vol. % of the solvent by using asphaltene precipitant additives. However, all the asphaltene precipitants tested are solids at room and reservoir temperatures. Their use in the presence of the porous media is limited to near the wellbore either in the presence of steam or warm solvents. Therefore, unfortunately, little to no penetration into the formation and further away from the injection wellbore is expected.
It would be desirable to provide improved processes for in situ upgrading of heavy crude oils that can be carried out with low operating and capital expenses in a simple and cost-efficient manner and at the same time extend into the formation a significant distance.

Method of selection of asphaltene precipitant additives and process for subsurface upgrading therewith


Method for protecting the surface of wind turbine blades manufactured with composites so as to furnish them with a finish resistant to normally-encountered external agents, namely rain, ice and grime from atmospheric pollution; and comprising one step for surface preparation as well as two steps for primer application and a second coating having a specified thickness.

Wind turbines are equipped with a rotor for supporting various blades radially extending from it to capture kinetic energy from the wind, causing the rotation of a drive train coupled to an electric generator to produce electricity.
Wind turbine blade performance is affected by modifications to its aerodynamic profile caused by various agents.
Blade surfaces erode as a result of impacts with rain drops, hail, insects, particles in suspension, etc. The erosion of the leading edge in particular has a highly significant effect on the performance of wind turbine blades.
Blade surfaces could also be altered by the adhesion of some external element. The accumulation of ice on the blade has such a significant effect on performance, that it could require the wind turbine to be stopped. The accumulation of a significant amount of grime also impairs blade performance.
The aforementioned performance issues are further aggravated in lengthy blades installed on wind turbines currently sold on the market.
Common practice in prior art entails applying polyurethane strips on the leading edge of the blades to protect them against, primarily, erosion. However, the effectiveness of these strips is contingent upon their correct placement on the leading edge, which cannot always be attained due to defects in placement or deterioration of the strip during blade transport to the wind turbine site. Additionally, polyurethane strips are facing a potential issue as the trend is to produce larger blades, consequently increasing the aerodynamic noise created by the blade.
Replacing these strips with chemical coatings could prove difficult given the variety of agents that could modify the aerodynamic profile of wind turbine blades.
This invention has been conceived to solve the aforementioned difficulties.

Method for optimizing the efficiency of wind turbine blades


A method and apparatus for antenna parameter notification is provided. At a device comprising at least one processor, an antenna, and a display, a parameter associated with performance of the antenna is determined at the processor. When the parameter meets a given criteria then the processor changes a brightness of the display.

Mobile devices are generally trending towards being slimmer (and even flexible), with MIMO (multiple-in-multiple-out) antennas. In such mobile devices, tuneable antennas and adaptive impedance matching techniques are important. However, for some cases, such dynamic techniques do not provide optimized radio performance. For example, device orientation, device shape, slider and/or flip position, hand position, interference between multiple radios, SAR (specific absorption rate) requirements and the like, all affect antenna performance due to resulting changes in coupling, out of tuning range, and the like.

Method and apparatus for antenna parameter notification


A Protective Makeup Brush Cleansing Kit, including elements of the user and/or soap and water is provided. The Protective Makeup Brush Cleansing Kit will clean makeup brush bristles and protect makeup brush bristles by keeping them covered and free from pollutants. The Protective Makeup Brush Cleansing Kit covers will also prevent the makeup brush bristles from being bent and warp which increases longevity.

Makeup brushes are products that sometimes are used and handled roughly and therefore are exposed to being distorted, brittle and un-sanitized which could result in skin irritations and blemishes. The materials used for the makeup brushes are typically made of polyester and nylon and do not have a high longevity life. The recent trends towards preserving makeup brushes causes the makeup brush bristles to become distorted, warped and broken. In particular, the makeup brushes become bent and crushed when the makeup brushes are stuffed in makeup cases, purses and/or suitcases. Makeup brushes that are warped, brittle and distorted will not allow the makeup application to be applied correctly. Makeup brushes left without any protective covering can become filled with airborne bacteria, dust and can lead to blemishes, skin irritations and rashes.


Code, data, and/or other information types, may be isolated from one another and stored in distinct regions within the memory array of a nonvolatile memory. The distinct regions in memory may have corresponding read/write interfaces that are optimized for each information type.

Nonvolatile memories may be used to store numerous disparate code and data types. Usage patterns for these data types have different characteristics that may affect the memory device in which they are stored in different ways.
For example, a typical flash memory device may store both execute in place (XIP) code as well as multimedia data. XIP code is typically infrequently updated and frequently read. Thus, XIP code can tolerate slow in-system write performance, requires fast, deterministic initial access, and tends to induce and be affected by read disturb mechanisms. Multimedia data, on the other hand, is typically frequently updated and infrequently read. Thus, multimedia data can tolerate slow and/or nondeterministic initial access times, requires high performance writes, and tends to induce and be affected by charge loss/gain mechanisms.
FIG. 1 is a graph (100) illustrating the initial cell state distribution for code and data. The X-axis (104) indicates the memory cell state, and the Y-axis (102) indicates the fraction of memory cells in a given state. When code and data are initially written to a memory device, the cell states are clearly defined in State A (106) and State B (108). A relatively large separation (110) exists between those cells in state A and state B, and thus it is relatively easy to detect the difference between state A and state B when reading the memory cell(s). Initially, this is true regardless of the type of data stored in the memory cell.
However, over time the XIP code may be infrequently refreshed and frequently read, as described above. This may cause disturbs on the states of the data stored in memory, which may cause the state distribution for code cells to shift to the right. Similarly, multimedia data may be frequently rewritten and infrequently read, causing a different type of memory disturb to occur. These disturbs may cause the state distribution for the data cells to shift to the left.
FIG. 2 is a graph (200) illustrating the cell state distribution for code and data after cell state disturbs have occurred. Due to the disturbs, the cell state distributions for cells in state A (206) and state B (208) have widened, and may overlap (210). Thus, it can be very difficult to identify a proper reference placement in order to discern the difference between states. This may lead to errors when performing a read of the cells.

Memory architecture for separation of code and data in a memory device