An insoluble polymer is deposited in a body cavity for instance to embolize a vein or pack an aneurysm, the polymer having pendant zwitterionic groups to improve biocompatibility. The insoluble polymer is preferably formed by an in situ gelling step in which a charged, preferably soluble, polymer having pendant zwitterionic groups is introduced in the form of a composition in which it is soluble and is gelled by being mixed with a counterionically charged soluble polymer (polyelectrolyte), to form a polyion complex. Preferably the or each soluble polymer is formed by polymerizing ethylenically unsatured monomers including a zwitterionic monomer, for instance 2-methacryloyloxyethyl-2xe2x80x2-trimethylammoniumethyl phosphate inner salt, an ionic monomer such as trimethylammonium alkyl(alk)acrylate or a sulphoalkyl(alk)acrylate and optionally a diluent monomer such as an alkyl(alk)acrylate.

The present invention relates to the use of a polymer in a method of treatment in which it is introduced into a body cavity under conditions whereby insoluble polymer is deposited in the body cavity. In the invention polymer having pendant zwitterionic groups is used, whereby biocompatibility is optimised.
The current chosen method for the treatment of aneurysms involves the packing of the aneurysm with platinum coils. Some work has been performed on the coating of these coils to provide a surface with increase thrombogenicity and render it biologically active by enabling the release of cellular growth factors and the like (German Patent DE-A-19647280). Others have concentrated on the use of polymer systems for embolising aneurysms, often simply by precipitating the polymer from a solution in a biocompatible solvent (WO-A-9745131). Specifically, a Japanese Group has had some success using a liquid composition containing a hardening polymer (cellulose acetate), with an X-ray contrast agent in a solvent such as DMSO. The polymer is caused to precipitate in-situ within the aneurysm when contacted with blood (JP-A-06-107549, J. Neurosurg., 83(3), 531, 1995). Another approach has been to directly polymerise monomers in-situ, an example of which is a iron-acrylic compound which polymerises rapidly and is non-toxic (J.Neurosurg., 47(2), 137, 1977). Yet another approach described in U.S. Pat. No. 5,749,894 is to introduce a coil and a polymeric composition which is melted by incident radiation and re-solidified in situ in the aneurysm. Examples of polymers are polyalkenes, poly(meth)acrylates, polyesters, polyamides and polysaccharides.
The use of polyion complexes in medical applications has been suggested for many years. Indeed, Michaels made reference to the use of such complex solutions for potting or encapsulating aneurysms, commenting that the materials were reasonably well tolerated by the tissue. Ioplex 101 (a complex poly(triethyl-(3 and 4)-vinylphenylammonium bromide) and poly(sodium vinyl benzenesulphonate)) has been examined intensively for biomedical usage (Vogel et al. J.Macromol. Sci., Chem., 4, 675, 1970; Marshall et al., J. Biomed Mater. Res., 4, 357, 1970; Bruck et al., Ann. N.Y. Acad Sci., 283, 332, 1977). Analogues of this system have been studied to determine the effect of charge and structure on the complex and their behaviour towards blood platelets (Kataoka et al., Makromol. Chem., 179, 1121, 1978 and 181, 1363, 1980) and have been used as encapsulating agents in the development of artificial liver support systems (Kataoka et a., Jinko Zoki (Artificial Organs), 8 296, 1979).
Nakabayashi et al. have previously described the use of polyion complexes of polymers having zwitterionic pendant groups for the selective adhesion of platelets (J. Biomed. Mater. Res., 28(11), 1347, 1994 by Ishihara, K. et al. Adv. Biomat. Biomed. Eng. Drug Delivery Syst. (1995) 227-228 by Ishihara, K. et al., and Japanese Patent JP-A-7-238124). Their invention claims specifically the use of a ternary polymer system consisting of 2-methacroyoyloxyethyl phosphorylcholine (MPC), butyl methacrylate (BMA) and sulfopropyl methacrylate (SPM) or trimethyl ammonium propyl methacrylate (TPM). Further to this, they define the compositions in which the MPC:BMA molar ratio is between 2:98-50:50, and the ratio of these two components to the ionic monomer (SPM or TPM) is between 98:2-80:20. These systems seem to have been designed to produce coatings with weak ionic interactions that have favourable properties in terms of platelet binding and activation. The polyion complexes described in these references are tested as coatings on glass beads and one of the products is said to be under test for use to encapsulate activated charcoal used for an artificial liver support system.
In the present invention there is provided a new use of a charged polymer in a method of manufacture of a composition for use in the method of treatment of a human or animal by therapy or diagnosis in which the charged polymer containing composition is introduced into a body cavity and is contacted with a separate composition comprising a polyvalently charged counterion whereby the polymer is rendered insoluble in the body cavity, and is characterised in that the charged polymer has zwitterionic pendant groups.
The present invention also includes the method of treatment itself.
In the present invention, the insoluble polymer is deposited as a gel in the body cavity. The polymer should be insoluble in situ, so that it remains in situ over a period of time, for instance at least several hours, days or weeks. A gel comprises a matrix of polymer and solvent distributed throughout the matrix. Preferably the solvent in the gel is aqueous and substantially free of organic solvent.
The gel depot may be used as a vehicle for delivery to the body cavity of therapeutically active agents, or diagnostic agents such as contrast agents. Contrast agents may, for instance, be introduced to allow medical practitioners to visualise the position of the insoluble polymer, which itself may be providing a therapeutic benefit, or diagnostic utility in a patient. According to a preferred aspect of the invention therefore the insoluble polymer is, in the body cavity, combined with a therapeutically active or imaging agent.
The gelled polymer may be a coating, or encapsulating agent, on particulate or non particulate solid material which is opaque to electromagnetic radiation (possibly radio frequency). The opaque material may, for instance, be an imaging agent such as described in U.S. Pat. No. 5,667,767 such as tantalum, tantalum oxide and barium sulphate, or as described in U.S. Pat. No. 5,695,480 including gold, tungsten and platinum. The opaque agent may be particulate or may be a solid material having a discrete physical shape, for instance being 1 mm or larger in size such as a metallic coil, filament, wire, mesh or tube. For instance coils as described in U.S. Pat. Nos. 4,994,069, 5,122,136, 5,226,911 or U.S. Pat. No. 5,702,361 may be included.
The present invention is particularly useful for embolising blood vessels, or for packing aneurysms. The polymer is thus used in methods analogous to those described in the prior art discussion above. The invention may also be used as a therapeutic or cosmetic filler, for instance for use following tumour excision, for enhancing lips or breasts, for improving muscle control, for instance sphincter muscles to control incontinence, for endoluminal gel paving, for the treatment of patent ductus arteriosus, or for replacement or supplement of synovial fluid.
The charged polymer is prior to insolubilisation, soluble, in the composition in which it is introduced into the body cavity. That composition is preferably aqueous. The polymer is thus preferably water-soluble. The counterion is also preferably soluble in the separate composition in which it is introduced into the body cavity. It is most convenient for the separate composition to be aqueous, so that it is preferred for the counterion to be introduced in a water-soluble form, in solution in an aqueous composition.
The two compositions may be mixed in the body cavity or immediately before being introduced into the body cavity. Preferably they are introduced using a catheter designed for the purpose, which has separate lumens for each composition and means for allowing contact and mixing of the compositions immediately before delivery of the insoluble, usually gel form, polymer from the catheter into the desired location in a body cavity.
The counterion may be inorganic or organic. It may be a di- or tri-valently charged soluble ion, for instance a metal cation, or a multivalent oxyanion. Calcium ions are suitable multivalent cations.
Preferably in the invention, the counterion is a polyelectrolyte. The counterionic charges of the two polymers attract one another when the polymers are intimately mixed, thereby insolubilising (gelling) the blend. This blend is consequently a polyion (or polyelectrolyte) complex. At least one of the polymers forming the polyion complex should have zwitterionic pendant groups. Preferably both polymers have zwitterionic pendant groups. The charged polymer which has an essential feature pendant zwitterionic groups, may be anionic or cationic but is preferably anionic. The counterion is thus preferably cationic.
In some embodiments of the present invention, a polycationic polymer will have permanently cationic pendant groups. These may be quaternary ammonium or phosphonium or tertiary sulphonium groups. In other embodiments, the cationic group may not be a permanent cation. It may be a weak or a strong base. For instance it may be selected so as to provide pH sensitivity whereby the degree of attraction between the two first polymers may be controlled by the pH.
Likewise, the anion may be the anion of a weak or strong acid, selected so as to be pH sensitive or insensitive within a predetermined pH range, as desired.
A suitable cationic group is a group N+R13, P+R13 or S+R12
in which the groups R1 are the same or different and are each hydrogen, C1-4-alkyl or aryl (preferably phenyl) or two of the groups R1 together with the heteroatom to which they are attached from a saturated or unsaturated heterocyclic ring containing from 5 to 7 atoms. Preferably the cationic group is permanently cationic, that is each R1 is other than hydrogen. Preferably the cationic group is N+R13 in which each R1 is C1-4-alkyl, preferably methyl.
Suitable anionic groups are carboxylate, carbonate, sulphonate, sulphate, phosphonate or phosphate. Preferably the anionic group is monovalent. A sulphonate group is particularly convenient.
In a polyion complex used in the invention, the polycationic polymer and polyanionic polymer are preferably used in ratios so as to provide a ratio of equivalents of cationic groups and anionic groups in the range 2:1 to 1:2. Preferably the anions are present in approximately equivalent amount to the cation so that the ratio is preferably in the range 1.5:1 to 1:1.5, or preferably 1.2:1 to 1:1.2, for instance about 1:1.
In the gelled condition the level of zwitterionic groups is preferably in the range 1 to 75 mole %, preferably 20 to 50%, based on the total moles of monomer from which the polymer(s) forming the insoluble polymer are formed (in the preferred embodiment where the charged polymer(s) is formed from ethylenically unsaturated monomers including zwitterionic monomer).
The amount of ionic monomer in an ionic polymer comprised in the charged polymer is preferably at least 1 mole %, more preferably at least 5 mole %, for instance at least 10 mole %. Where the amount is higher than about 30 or 40 mole % (and the counterionic charges in a PIC are approximately balanced) the or each polymer should preferably also include at least 20%, preferably at least 30% zwitterionic monomer.
For the preferred embodiment in which the charged polymer comprises at least one ionically charged polymer including zwitterionic pendant groups, the ratio of zwitterionic ionic groups is preferably in the range 5:1 to 1:5, preferably 2:1 to 1:3.
The total content of ionic and zwitterionic monomer in the charged polymer and in preferred counterion is preferably at least 25 mole %, more preferably at least 30%, more preferably at least 40%, up to 100%, more preferably up to 80%, most preferably in the range 50 to 70%. The remaining components of the polymer(s) are non-ionic monomer, which may act primarily as diluent or may confer desirable physical properties on the polymer(s). A non-ionic, monomer may comprise a hydrophobic pendant group.
The ratio of anionic to cationic polymer and the relative amounts of zwitterionic and hydrophobic diluent groups in a polyion complex may be judged by determining the gel properties of a gel, usually an aqueous gel formed by mixing the counterionic polymers from solutions each containing one of the polymers. A suitable technique for investigating the gel properties is described in Example 3 below.
The zwitterionic pendant group of the polymer used in the invention may have an overall charge, for instance by having a divalent centre of anionic charge and monovalent centre of cationic charge or vice versa or by having two centres of cationic charge and one centre of anionic charge or vice versa. Preferably, however, the zwitterion has no overall charge and most preferably has a centre of monovalent cationic charge and a centre of monovalent anionic charge.
Preferably the centre of cationic charge in the zwitterionic group is permanent, that is it is preferably a quaternary ammonium or phosphonium or a tertiary sulphonium group. Preferably the anion is permanent, that is it is substantially completely ionised at in vivo pH""s, for instance at pH""s in the range 5 to 8. It is preferably a phosphate, phosphonate, sulphate or sulphonate anion.
The zwitterionic group may be a betaine group (ie in which the cation is closer to the backbone than the anion), for instance a sulpho-, carboxy- or phospho-betaine. A betaine group should have no overall charge and is preferably a carboxy- or sulpho-betaine. If it is a phosphobetaine the phosphate terminal group must be a diester, i.e., be esterified with an alcohol. Such groups may be represented by the general formula I
xe2x80x94X2xe2x80x94R2xe2x80x94N.(R3)2xe2x80x94R4xe2x80x94V⊕xe2x80x83xe2x80x83I
in which
X2 is a valence bond, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94NHxe2x80x94, preferably xe2x80x94Oxe2x80x94;
V is a carboxylate, sulphonate or phosphate diester(monovalently charged) anion;
R2 is a valence bond (together with X2) or alkanediyl, xe2x80x94C(O)alkanediyl- or xe2x80x94C(O)NHalkanediyl preferably alkanediyl and preferably containing from 1 to 6 carbon atoms in the alkanediyl chain;
the groups R3 are the same or different and each is hydrogen or alkyl of 1 to 4 carbon atoms or the groups R3 together with the nitrogen to which they are attached form a heterocyclic ring of 5 to 7 atoms; and
R4 is alkanediyl of 1 to 20, preferably 1 to 10, more preferably 1 to 6 carbon atoms.
One preferred sulphobetaine monomer has the formula II
where the groups R5 are the same or different and each is hydrogen or C1-4 alkyl and n is from 2 to 4.
Preferably the groups R5 are the same. It is also preferable that at least one of the groups R5 is methyl, and more preferable that the groups R5 are both methyl.
Preferably n is 2 or 3, more preferably 3.
Alternatively the zwitterionic group may be an amino acid moiety in which the alpha carbon atom (to which an amine group and the carboxylic acid group are attached) is joined through a linker group to the backbone of polymer A. Such groups may be represented by the general formula III
in which
X3 is a valence bond, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94 or xe2x80x94NHxe2x80x94, preferably xe2x80x94Oxe2x80x94,
R6 is a valence bond (optionally together with X3) or alkanediyl, xe2x80x94C(O)alkanediyl- or xe2x80x94C(O)NHalkanediyl, preferably alkanediyl and preferably containing from 1 to 6 carbon atoms; and
the groups R7 are the same or different and each is hydrogen or alkyl of 1 to 4 carbon atoms, preferably methyl, or two of the groups R7, together with the nitrogen to which they are attached, form a heterocyclic ring of from 5 to 7 atoms, or the three group R7 together with the nitrogen atom to which they are attached form a fused ring structure containing from 5 to 7 atoms in each ring.
Preferably the zwitterion has the formula IV
in which
the moieties X4 and X5, which are the same or different, are xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NHxe2x80x94 or a valence bond, preferably xe2x80x94Oxe2x80x94, and
W+ is a group comprising an ammonium, phosphonium or sulphonium cationic group and a group linking the anionic and cationic moieties which is preferably a C1-12-alkanediyl group.
Preferably W contains as cationic group an ammonium group, more preferably a quaternary ammonium group.
The group W+ may for example be a group of formula xe2x80x94W1xe2x80x94N+R83, xe2x80x94W1xe2x80x94P+R93, xe2x80x94W1xe2x80x94S+R92 or xe2x80x94W1-Het+ in which:
W1 is alkanediyl of 1 or more, preferably 2-6 carbon atoms optionally containing one or more ethylenically unsaturated double or triple bonds, disubstituted-aryl, alkylene aryl, aryl alkylene, or alkylene aryl alkylene, disubstituted cycloalkyl, alkylene cycloalkyl, cycloalkyl alkylene or alkylene cycloalkyl alkylene, which group W1 optionally contains one or more fluorine substituents and/or one or more functional groups; and
either the groups R8 are the same or different and each is hydrogen or alkyl of 1 to 4 carbon atoms, preferably methyl, or aryl, such as phenyl or two of the groups R8 together with the nitrogen atom to which they are attached form a heterocyclic ring containing from 5 to 7 atoms or the three groups R8 together with the nitrogen atom to which they are attached form a fused ring structure containing from 5 to 7 atoms in each ring, and optionally one or more of the groups R8 is substituted by a hydrophilic functional group, and
the groups R9 are the same or different and each is R8 or a group OR8, where R8 is as defined above; and
Het is an aromatic nitrogen-, phosphorus- or sulphur-, preferably nitrogen-, containing ring, for example pyridine.
Preferably W1 is a straight-chain alkanediyl group, most preferably 1,2-ethanediyl.
Preferred groups of the formula IV are groups of formula V:
where the groups R10 are the same or different and each is hydrogen or C1-4 alkyl, and m is from 1 to 4.
Preferably the groups R10 are the same. It is also preferable that at least one of the groups R10 is methyl, and more preferable that the groups R10 are all methyl.
Preferably m is 2 or 3, more preferably 2.
Alternatively the ammonium phosphate ester group V may be replaced by a glycerol derivative of the formula VB, VC or VD defined in our earlier publication no WO-A-93/01221.
Preferably the polymer or polymers having a pendant zwitterionic group are wholly synthetic, although under some circumstances it may be desirable to use derivatives of natural polymers. Preferably the polymer(s) is formed from radical polymerisable ethylenically unsaturated monomers including a monomer of the formula VI
YBXxe2x80x83xe2x80x83VI
wherein
B is a straight or branched alkanediyl, alkanediyloxaalkanediyl or alkanediyloligo(oxaalkanediyl) chain optionally containing one or more fluorine atoms up to and including perfluorinated chains or, if X or Y contains a terminal carbon atom bonded to B, a valence bond;
X is the zwitterionic group; and
Y is an ethylenically unsaturated polymerisable group selected from
xe2x80x83CH2xe2x95x90C(R)xe2x80x94CH2xe2x80x94Oxe2x80x94, CH2xe2x95x90C(R)xe2x80x94CH2OC(O)xe2x80x94, CH2xe2x95x90C(R)OC(O)xe2x80x94, CH2xe2x95x90C(R)xe2x80x94Oxe2x80x94, CH2xe2x95x90C(R)CH2OC(O)N(R11)xe2x80x94, R12OOCCRxe2x95x90CRC(O)xe2x80x94Oxe2x80x94, RCHxe2x95x90CHC(O)Oxe2x80x94, RCHxe2x95x90C(COOR12)CH2xe2x80x94C(O)xe2x80x94Oxe2x80x94,
xe2x80x83wherein:
R is hydrogen or a C1-C4 alkyl group;
R11 is hydrogen or a C1-C4 alkyl group or R11 is xe2x80x94Bxe2x80x94X where B and X are as defined above; and
R12 is hydrogen or a C1-4 allyl group or BX where B and X are as defined above;
A is xe2x80x94Oxe2x80x94 or xe2x80x94NR11xe2x80x94;
K is a group xe2x80x94(CH2)pOC(O)xe2x80x94, xe2x80x94(CH2)pC(O)Oxe2x80x94, xe2x80x94(CH2)pOC(O)Oxe2x80x94, xe2x80x94(CH2)pNR13xe2x80x94, xe2x80x94(CH2)pNR13C(O)xe2x80x94, xe2x80x94(CH2)pC(O)NR13xe2x80x94, xe2x80x94(CH2)pNR13C(O)Oxe2x80x94, xe2x80x94(CH2)pOC(O)NR13xe2x80x94, xe2x80x94(CH2)pNR13C(O)NR13xe2x80x94 (in which the groups R13 are the same or different), xe2x80x94(CH2)pOxe2x80x94, xe2x80x94(CH2)pSO3xe2x80x94, or, optionally in combination with B, a valence bond and p is from 1 to 12 and R13 is hydrogen or a C1-C4 alkyl group;
Preferably Y is a group CH2xe2x95x90C(R)COAxe2x80x94, in which R is H or methyl, preferably methyl, and in which A is preferably O.
B is preferably an alkanediyl group of 1 to 12, preferably 2 to 6 carbon atoms, most preferably group (CH2)q in which q is 2 to 6.
Where the polymer having a zwitterionic group is part of a polyion complex, the polymer is formed by including in the ethylenically unsaturated monomers an ionic monomer of the formula VII
Y1B1Qxe2x80x83xe2x80x83VII
in which
Y1 is selected from the same groups as Y;
B1 is selected from the same groups as B; and
Q is an ionic group or ionisable.
Q may be a cationic group Q1 or an anionic group Q2. A cationic group Q1 is preferably as described above. An anionic group Q2 is preferably selected from the groups listed above.
Another suitable type of cationic monomer copolymerisable with ethylenically unsaturated monomers is diallyl dialkyl ammonium halide, for instance diallyl dimethyl ammonium chloride.
The ethylenically unsaturated monomers preferably further comprise nonionic monomer. The nonionic monomer may be selected so as to confer desired solubility, hydrophilicity or hydrophobicity properties upon the polymer bearing zwitterionic pendant groups. The nonionic monomer may also confer on the polymer physical characteristics which affect the mechanical characteristics of the insoluble polymer in situ. For instance hydrophobic groups may provide inter or intramolecular interactions with other hydrophobic groups, or with substrates or biological compounds in situ which render the insoluble polymer particularly suitable for the desired application.
Preferably a nonionic monomer has the general formula VIII
Y2R14xe2x80x83xe2x80x83VIII
in which
Y2 is selected from the same groups as Y; and
R14 is a nonionic organic group which is an optionally substituted C1-24-alkyl or -alkenyl group. Optional substituents in the alkyl or alkenyl group are hydroxyl groups; halogen atoms, alkoxy and oligo-alkoxy groups, in which the alkoxy groups have 1-6, preferably 2 or 3 carbon atoms; aryl groups, preferably optionally substituted phenyl groups; optional substituents in a phenyl group being hydroxyl, halogen atoms or alkyl groups; acyl groups, especially C1-6-alkanoyl groups; acyloxy groups, especially C1-6-alkanoyloxy groups; acylamino groups, especially C1-6-alkanoyl amino, in any of which alkanoyl groups there may be substituents selected from halogen atoms and hydroxyl groups, and alkoxy groups. Preferred groups R14 are C1-24-unsubstituted alkyl, more preferably C4-18-alkyl.
A nonionic monomer is preferably present in the ethylenically unsaturated monomers from which the charged polymer and/or the counterionic polyelectrolyte are formed in a molar amount in the range 1-75%, preferably 20 to 70%, more preferably 30-50%.
A particularly preferred use of the invention is in the treatment of aneurysms. The charged polymer and counterion could be mixed via a catheter, in the form of aqueous solutions or dispersions, to form a gel in situ within the aneurysm void. Once filled the aneurysm would have no void space for the blood to occupy and the danger of rupture of the blood vessel would be removed.
The zwitterionic groups of the gelled (insoluble) polymer are believed to confer biocompatibility, minimising response from the inner lining of the aneurysm or other tissue or biological fluids in contact with the second polymer in the body cavity.


A braking device for bicycle provided with two wire brake systems is disclosed. There is provided a relay amid outer tubes of both brakes to which divided ends of the outer tubes are connected and both continuous brake wires are fixed together inside the relay after individual adjustment. It is then possible to actuate the two brake systems simultaneously by manipulation of either brake lever and proper adjustment is feasible with ease for it can be done independently before fixing of both wires.

1. Field of the Invention
The present invention relates to improvement of a braking device for bicycle wherein two braking systems can be actuated simultaneously by manipulation of a single brake lever.
2. Description of the Prior Art
As prior arts for simultaneous braking device for bicycle there are known, among others, Japanese Patent Publication No. 55 (1980)-22312 and No. 3 (1991)-23394. With each thereof two independent lines of brake wires are divided amid into four parts in total and each end thereof is connected to a movable plate.
Hitherto, it has been taken as preferable to have braking of the front wheel effected later than that of the rear wheel. In the aforementioned prior arts attempts were made for delaying braking of the front wheel such as providing a backlash for the connection between the wire and the movable plate. For that, however, it was necessary to first adjust either brake before adjusting the other brake with its stroke matched, this resulting in decrease of the wife's effective stroke. And this gave rise to a problem that it was then difficult to adjust the gap between the wheel and the brake shoe to be proper for both wheels. Such adjustment was extremely difficult when there were such factors as loosening of the connection with the moving plate, scattering in dimension of the parts involved, deformation of the wheels et cetera, these possibly resulting in failure of braking or of releasing thereof. Worse, with the wire divided into four, there resulted in increase of the number of the parts involved as well as of the man-hours required for assembly and also in relative increase in size of the movable plate which affected the aesthetic quality thereof.
It is the object of the present invention to solve such problems about the prior arts, that is, to provide a braking device with which adjustment of the gap between the wheel and the brake shoe is easy and which functions always satisfactorily. Another object of the invention is to provide a braking device with which braking of the front and rear wheel is effected simultaneously. A further object of the invention is to provide a braking device decreased in the number of parts involved or the man-hours required for assembly and improved in aesthetic quality.
In order to accomplish the aforementioned object, the braking device for bicycle of the present invention comprises two wire brake systems in which two brake wires are led from each brake lever through the outer tube to each brake and, when either brake lever is manipulated, the two brakes are actuated simultaneously. In such braking device there is provided an outer tube relay amid the outer tubes for both brakes for divided ends of the outer tubes to be connected thereto and a fixing means for fixing together two continuous brake wires leading from each brake lever to each brake inside the outer tube relay. The construction described above allows independent adjustment of each wire brake system before fixing together both brake wires, hence an effective stroke can be secured for each brake wire and each brake can be actuated without fail. Since the size of the outer tube relay suffices if it is enough for fixing together both brake wires, there is no problem of it being bulky to affect the aesthetic quality thereof. Also, such brake can be attached easily to an old bicycle in use.


A UE may be operating in a wireless communication network having a UE-centric medium access control layer, and the UE may detect presence of a trigger event to signal a base station of the wireless communication network. The UE may identify one of a plurality of functionalities corresponding to the trigger event, and may generate a chirp signal that includes chirp purpose indicator and a chirp message, wherein the chirp purpose indicator and a format of the chirp message correspond to the identified one of the plurality of functionalities. Accordingly, the UE may transmit the chirp signal having the chirp purpose indicator to the base station, which may provide a chirp response message that includes message contents that relate to the chirp purpose indicator.

Aspects of the present disclosure relate generally to wireless communication networks, and more particularly, to chirp signal formats and techniques in a wireless communication network.
Wireless communication networks are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems, and single-carrier frequency division multiple access (SC-FDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. For example, a fifth generation (5G) wireless communications technology (which can be referred to as new radio (NR)) is envisaged to expand and support diverse usage scenarios and applications with respect to current mobile network generations. In an aspect, 5G communications technology can include: enhanced mobile broadband addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable-low latency communications (URLLC) with certain specifications for latency and reliability; and massive machine type communications, which can allow a very large number of connected devices and transmission of a relatively low volume of non-delay-sensitive information. As the demand for mobile broadband access continues to increase, however, further improvements in 5G communications technology and beyond may be desired.
For example, for 5G communications technology and beyond, current network-centric media access control (MAC) layer technologies may not provide a desired level of resource utilization and/or efficiency because of the various associated signal broadcasts. For instance, these broadcasts consume power and may or may not be received or used by some or all of a cell's served user equipments (UEs). Thus, improvements in wireless communication network operations may be desired.


A method for diagnosing a condition of a patient includes providing a color reference member that includes one reference color thereon. An electronic visual image is obtained of a patient tissue and the at least one reference color on the image. The electronic visual image is processed with the computer by analyzing the colors in the image of the patient tissue and the reference color. This analysis is performed to obtain a standardized color value of the patient tissue. A condition of the patient is diagnosed by using the standardized color value of the patient tissue so obtained.

Biological tissue substances are imbued with color that is observable under a visible light. The colors of some substances, such as skin, hair and teeth will often differ widely between individuals, and are used as identifying markers to identify the individual to whom the particular tissue sample belongs.
All colored bio-substances will exhibit the color-based functionalities that one might expect, such as a reflection, transmission and refraction of light of various wave lengths.
The colors of biological tissues are often determined by genetic factors. For example, the fact that a particular individual has brown hair rather than blond hair is a reflection of the genetic make-up of the person's parents whose genetic make-up, along with Mendelian chance conspire to cause the person to be a brunette.
Along with being a genetic marker, the color of a particular biological tissue is often reflective of the state of health of either or both of the tissue itself and the organism from which the tissue came. For centuries, healthcare practitioners have observed the colors of body tissues, such as the color of a person's skin, eyes, lips, tongue, fingernails or toenails to determine whether a person has a particular disease condition. For example, the existence of a yellowish coloration of a person's skin is often indicative of diseases or abnormal conditions of the liver and/or gallbladder. Additionally, people also use facial color changes to identify stress, anger, cold, alcohol over indulgence and other health-related conditions.
Modern medical practice often relies on color changes to diagnose and/or monitor conditions. For example, the progress of skin cancer is often monitored through an observation of color changes of areas of abnormal skin, and the development of abnormal moles or pigmentations, that are employed to identify possible growth of cancerous cells.
One of the difficulties with using color identification is that it is difficult to calibrate the colors observed, so that one can easily compare observed colors against either a known standard, or against subsequent observations. Although sophisticated scientific instruments exist that measure color spectrums of material, most of such known medical instruments are expensive and require a special skill to operate. Most color-based tissue matching operations still rely on matching an observed color of a tissue by comparing it to a color chart to find an appropriate match.
Unfortunately, any such match relies to a large extent on the subjective observations of the viewer, along with being the type of observation to which it is very difficult to attach any quantitative measurements. Further, most such color observations are usually done by "hand", where an observer compares "actual" tissue sample against a particular color chart. As will be discussed below, the difficulties that currently exist in capturing "true color" images make color-based diagnoses that are made from color images (rather than the live tissue), very problematic and unreliable.
For a wide variety of reasons, the color of a tissue sample (or other object) that appears in a photographic image may differ significantly from the actual color (referred to herein as "true color") of the object.
One factor that will cause the image color to vary from the true color is the influence of the lighting condition that existed when the picture was taken. For example, images captured on film that are taken in a room lighted with a fluorescent light, such as is common in most offices, will tend to have a "colder" or "bluer" appearance, whereas images that are taken wherein the ambient light is provided by Tungsten-based light bulb will tend to have a "warmer" coloration that is more biased toward orange and red hues, rather than blue hues.
Another factor that will cause color to vary in an image captured on film is the manner in which the film is "constructed". When creating a color film composition, the film manufacturer strives not only to produce a film that reproduces colors accurately, but one that also reproduces colors in an aesthetically pleasing manner. Because purchasing decisions for film are often made by the purchaser based on the user's perceptions of the pleasingness of the colors of the pictures, film manufacturers will often bias their film products to balance the colors away from the "true colors" into more "pleasing" colors. In this regard, some films have a reputation of being "warm" films because their color balance is to bias their color balance in favor of the warmer colors (red and orange), and away from the colder (blue) colors. Other films are known as "colder films", since their color bias is toward colder, blue colors and away from warmer orange and red colors.
The developing and printing process can also introduce variations in colors. When a film is developed and printed, the technician, or the developer machine will select color balance for a print that may or may not reflect the actual true colors printed. Additionally, factors such as development time, chemical strength, temperature and the like can affect the hue and intensity of the colors shown in the pictures.
The upshot of the foregoing discussion is that it is very difficult, if not almost impossible, to achieve standardized colors when using conventional photography equipment. Since it is very difficult to standardize the color of a particular tissue sample in an image, it is difficult to use an image to analyze the color of the tissue sample to make an accurate diagnosis of the condition of the tissue sample, or more importantly, the condition of the patient from whom the tissue sample was taken.
Further, because of the inconsistency of the way in which colors are reproduced with conventional photograph equipment, it is difficult to track the progress of the condition by tracking changes of the color of a tissue sample shown in the image. It is difficult to track color changes, because a lack of standardization makes it difficult to determine whether a change in the apparent color of a tissue sample has resulted from an actual change in the color of the tissue sample, or rather, resulted from a change in the conditions under which the picture was taken, or a change in which the color was reproduced on the image.
As will be appreciated, those who are employing color to make a diagnosis would prefer to view images wherein the colors of the tissue samples and other contents of the image were standardized, and not subject to change under influence of lighting, development and the like.
To a large extent today, digital photography is replacing traditional film photography as the medium of choice for many photographic applications. Rather than capturing a picture on a film substrate, the image is captured on solid state sensors such as charge coupled devices (CCDs). CCDs consist of integrated circuits that contain an array of linked or coupled light sensitive capacitors. It is also known as a "color capture device". CCDs are often made from C-MOS devices that are complimentary metal-oxides semi-conductors.
Unfortunately, these CCD chips currently in use are not inherently better than film in capturing "true color". One reason that the CCD chips are no better than film is that CCD chips, when capturing an image, are still subject to the vagaries induced by the ambient light in which the image is being captured. Additionally, variations in color from "true color" can be introduced by camera components such as the camera lens materials, coatings used on lenses and the like. Further, the image captured by the CCDs of commercially available cameras usually undergo color "processing" by the cameras. The color processing by such cameras consists of these color images being processed by the software within the camera. Because most cameras are intended for the photographic and graphic arts markets, the camera companies have found that their digital camera products are better received when the output of the image captured by the CCD of the camera is processed so that the colors of the image are balanced and processed to look natural and be vivid and pleasing to the human eyes. As such, the cameras are designed to color bias the image to enhance the beauty of the picture, rather than to adjust the colors of the picture to reflect the true colors of the image. As discussed above, the use of the true colors would most likely create a picture image that was less aesthetically pleasing than one "balanced for beauty".
Unfortunately, those cameras do not allow an image to be captured without this processing; nor is it easy to reverse engineer this processing, as the algorithms and processing methods employed by the camera companies to so process their images are often maintained by the camera companies as trade secrets.
The goals of one performing a colorimetric analysis on a tissue sample are at odds with those desiring beautiful pictures. In order to make an appropriate colorimetric analysis of a color, it is important to be able to compare that color against a known standard, to help determine the differences between the color of a test subject and the color of the known standard. Additionally, if one is performing a colorimetric analysis on a large number of samples, to try to determine data relating to the comparative condition of the various samples, it is important to have the images of all of the test samples shot under generally identical conditions, so that differences in color reflect differences in actual tissue color, rather than reflecting differences in lighting, or color balance induced by the camera or its processor.
It is therefore one object of the present invention to provide a method and apparatus for facilitating the performance of a colorimetric analysis of a tissue sample by enabling the user to obtain a standardized color value of a patient tissue, that can then be used to better analyzing the condition of the patient. Preferably, this method can be performed with software and consumer affordable, commercially available hardware.

Method and apparatus for diagnosing conditions using tissue color


An embodiment provides a working medium to be used in a circular osmotic pressure electric power generation system. The working medium comprises water and an inducing-liquid. The working medium, under conditions of a temperature of 5° C. to 35° C. and a pressure of 1 atmosphere, is in (1) a state of a liquid-liquid mutually dissolved two-component mixed solution when a concentration of the water or the inducing-liquid in the total amount of the water and the inducing-liquid is 10% by weight or lower, and (2) a state of being separated into the water phase and the inducing-liquid phase when the concentration of the water or the inducing-liquid in the total amount of the water and the inducing-liquid is higher than 10% by weight.

When a solution having low concentration and another solution having high concentration are separated by an osmosis membrane (semi-permeable membrane), the solvent of the solution of low concentration permeate through the osmosis membrane to move to the side of the solution having high concentration. An osmotic pressure electric power generation apparatus which generates electric power by rotating the turbine by utilizing this solvent movement phenomenon is known.
There is another type of osmotic pressure electric power generation apparatus, which generates electric power by circulating a working medium within a closed system. For example, an electric power generation apparatus is known, which uses an aqueous solution of ammonium carbonate as a working medium. In this apparatus, the turbine is rotated by water flow created by the difference in osmotic pressure between two types of aqueous solutions of ammonium carbonate having different concentrations from each other. The portions of the ammonium carbonate aqueous solutions used to rotate the turbine are heated for reuse and are separated into gaseous carbon dioxide and gaseous ammonia, and an aqueous solution of ammonium carbonate having a very low concentration. The separated gaseous carbon dioxide and ammonia are reintroduced into water, thus obtaining an aqueous solution of ammonium carbonate having a very high concentration. Therefore, the two types of aqueous solutions of ammonium carbonate having different concentrations thus obtained are re-circulated and used for electric power generation.
Ammonium carbonate has such a good solubility that 100 g of ammonium carbonate dissolves into 100 mL if water at room temperature. With this solubility, it is possible to obtain an osmotic pressure of such a degree that fresh water can be filtered out from sea water (3.5% by weight). Also, ammonium carbonate decomposes at such a low temperature as 60° C. into a gaseous carbonate and gaseous ammonia. An osmotic pressure electric power generation apparatus which uses an ammonium carbonate aqueous solution generates electric power while sending the aqueous solution pressurized by a positive osmotic pressure to its turbine. Here, it is possible to obtain such a high pressure of 250 atmospheres as the osmotic pressure. This is reported as about 10 times high as the pressure involved in the osmotic pressure electric power generation which uses the osmotic pressure of sea water.
On the other hand, in the electric power generation which utilizes the positive osmotic pressure by ammonium carbonate, poisonous and corrosive gaseous ammonia is produced. The production of gaseous ammonia causes degradation within the system and greatly affects the running cost. Further, ammonium carbonate is easy to precipitate, or more specifically, for example, it immediately precipitates at less than 50° C. when used at 6 moles. Therefore, there is a risk in which precipitated crystals may cut the osmosis membrane when the temperature decreases near the membrane. This risk is particularly likely when the maintenance is carried out at room temperature. In order to reduce the risk of the crystal precipitation, it is unavoidable to drive the system at low concentration. As a result, it becomes difficult to obtain a sufficient osmotic pressure.

Circulatory osmotic pressure electric power generation system and method, phase control method for working medium, and working medium for circulatory osmotic pressure electric power generation


Shape memory alloy (SMA) actuating elements are commonly simpler and of lower mass than alternative actuator designs and may find particular application in the transportation industry. Such SMA-powered devices are usually reliable and long-lived but the phase transformations which occur in the SMA alloy and are responsible for its utility are not totally reversible. This irreversibility, a consequence of irrecoverable strain, may progressively degrade the long-term actuator performance as the irrecoverable strain accumulates over many operating cycles. Methods and devices for compensating for these effects and extending the useful cycle life of SMA actuators are described.

Many mechanical devices may adopt one of two substantially fixed configurations and are repeatedly cycled between two operating positions. These positions may be designated as off/on or open/closed or extended/retracted or engaged/disengaged or some similar terminology. Exemplary automotive examples of such devices include a retractable air dam, latches and clutches among others. Other mechanical devices may adopt, in addition to 'open' and 'closed' positions a range of positions intermediate between these limits. Exemplary automotive examples of such devices are a set of louvers for controlled passage of air which may be 'closed', 'open' 50% open, 85% open etc., a fluid flow valve, rearview or side mirrors or visors or shades. Both types of devices may be operated using mechanisms incorporating an elongated shape memory alloy (SMA) actuator.
SMA actuated devices find particular application in vehicles where their low mass coupled with their reliability and relative simplicity makes them attractive replacements for electromechanical devices such as electric solenoids or motors. This is particularly so when the stroke or range of operation of the device is limited.
SMA actuators rely for their operation on the useful property of SMA alloys that they may forcibly shrink or shorten in length when heated. The force generated by such SMAs is significant and may be powerful enough to operate a device even when some mechanical or other resistance is encountered.
A device may incorporate various components and mechanisms to achieve a desired range of motions but the key components of the SMA actuator are a preselected length of SMA alloy arranged in series with a biasing element which creates a biasing force to reset the device and prepares it for re-use. A common form of a biasing element is a spring but other approaches such as dead weights or hydraulic cylinders, among others, may be used. The SMA may suitably be in the form of wire, tape, chain, cable, braid or any other elongated form of SMA capable of sustaining a tensile load. The spring is commonly attached at one end to a support and at its other end to one end of the SMA wire, with the second end of the SMA wire attached to a second support. The workpiece or component to be moved is positioned between the wire and the spring. Mechanical stops may be employed to enforce only an intended range of motion.
SMAs derive their useful properties from their ability to exist in two crystalline phases, a first, lower modulus, phase stable at lower temperatures, and a higher modulus, higher temperature phase of a different crystal structure. The transition from one phase to the other may, by appropriate choice of alloy system, alloy composition, heat treatment or applied stress, be selected to occur over a temperature span of from −100° C. up to about +150° C. or so. But, many useful SMA alloys exist in their lower temperature or martensite phase, at, or slightly above, about 25° C. or so, and transform to their higher temperature, or austenite, phase at temperatures ranging from about 60°-80° C. or so. These characteristics substantially assure that the SMA will be in its martensite phase at ambient temperature but may be readily transformed to its austenite phase with only modest heating.
SMA actuator wires, or similar, are first shaped, in their austenite phase to the desired form, then cooled to ambient temperature, resulting in their adopting the martensite crystal structure. While in their martensite phase the wire is stretched and deformed to its intended predetermined length. The deformation exceeds the maximum allowable elastic strain which may be imposed on the actuator, and is often termed pseudo-plastic deformation. These pseudo-plastically-deformed martensite wires are in the appropriate starting condition for the actuator.
Generally the stretch or strain, that is, the change in length of the wire divided by its original or base length, applied during such pseudo-plastic deformation does not exceed 7% and more commonly may be 5% or less. Importantly, the base length, to which all length changes are referred, is the length of the wire in its high temperature, austenite phase.
After being suitably deformed in their martensite phase, the SMA wires may, when heated and transformed to austenite, spontaneously revert to their original undeformed shape. In changing shape, the wire will contract by an amount substantially equal to the pseudo-plastic strain previously applied when it was in its martensite phase. So, by suitable choice of wire length, any desired displacement may be achieved. As an example, a 10 inch or so length of wire, prestrained to about 5% strain, may enable a total displacement of about one-half inch or so. The force applied during heating may be increased by increasing the wire diameter, or, more commonly, to facilitate prompt cooling of the device, by arranging multiple smaller diameter wires in parallel.
Actuator action may be reversed by stopping heating and allowing the wire to cool to about ambient temperature and revert to its martensite crystal structure. During cooling the SMA wire will not spontaneously change its length to its initial deformed length but, in its martensite phase, it may be readily stretched again to its initial predetermined length. The spring, or other biasing element, in series with the SMA wire is selected to deform the SMA when the SMA is in its less strong martensite phase. So, on cooling, when the austenite wire reverts to its martensite phase it is stretched, by the spring, to its initial length so that the cycle may be repeated. Provided the transition in crystal structure is fully reversible this cycle of extending and contracting the wire by application of suitable stimulus may continue indefinitely.
In practice however, the phase transitions and the accompanying cyclic length are not completely reversible, and some irrecoverable deformation occurs. These cycle-by-cycle irreversibilities accumulate over repeated cycles to permanently extend the wire. This permanent extension of the wire introduces slack into the initially-taut wire and both reduces the stroke obtainable from a device and renders its operation non-linear. These effects may be sufficient to impair the operation of the device or render it ineffective. In such a circumstance the device may need to be replaced.
There is therefore a need to mitigate the effects of irreversible transformation of SMA actuators in devices to extend the useful cycle life of such devices.

Compensating for incomplete reversal in mechanisms incorporating shape memory alloy wire


Technology for an apparatus is described. The apparatus can include a memory controller with circuitry configured to define a caching and processing priority policy for one or more input/output (I/O) request class types. The memory controller can monitor one or more I/O contexts of one or more I/O requests. The memory controller can associate the one or more I/O contexts with one or more I/O class types using an I/O context association table. The memory controller can execute the one or more I/O requests according to the caching and processing priority policy of the one or more I/O class types. The apparatus can include an interface to the memory controller.

Given the complexity of computer systems, data, and the processing of data, challenges may arise for a computer storage system in attempting to differentiate between specific data types. In addition, computer storage systems are often unable to differentiate between classes of data or metadata due to limitations on the type of interface (e.g., a block interface), and the lack of a specific data-distinguishing mechanism. Thus, the computing performance may be negatively impacted.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation on disclosure scope is thereby intended.

Efficient context based input/output (I/O) classification


This document describes an interactive object with multiple electronics modules. An interactive object (e.g., a garment) includes a plurality of conductive threads woven into the interactive object, and an internal electronics module coupled to the array of conductive thread. The internal electronics module includes a first subset of electronic components, such as sensing circuitry configured to detect touch-input to the grid of conductive thread. An external electronics module that includes a second subset of electronic components (e.g., a microprocessor, power source, or network interface) is removably coupled to the interactive object via a communication interface. The communication interface enables communication between the internal electronics module and the external electronics module when the external electronics module is coupled to the interactive object.

An interactive textile includes conductive thread woven into the interactive textile to form a capacitive touch sensor that is configured to detect touch-input. The interactive textile can process the touch-input to generate touch data that is useable to initiate functionality at various remote devices that are wirelessly coupled to the interactive textile. For example, the interactive textile may aid users in controlling volume on a stereo, pausing a movie playing on a television, or selecting a webpage on a desktop computer. Due to the flexibility of textiles, the interactive textile may be easily integrated within flexible objects, such as clothing, handbags, fabric casings, hats, and so forth.
The interactive textile includes a grid or array of conductive thread woven into the interactive textile. Each conductive thread includes a conductive wire (e.g., a copper wire) that is twisted, braided, or wrapped with one or more flexible threads (e.g., polyester or cotton threads). It is difficult, however, for manufacturers to attach individual conductive threads to electronic components that may include electronics such as a processor, battery, wireless unit, sensors, and so forth.

Connector integration for smart clothing


In a hydraulic drive system of a work machine which drives a plurality of actuators using three or more pumps, for an operation not including traveling, a highly efficient combined operation in a front implement and excellent combined operability of a swing and the front implement are enabled, while for an operation including traveling, a highly efficient traveling operation and a highly efficient combined operation of traveling and the front implement are enabled, and a sufficient operation speed of the front implement is achieved. To this end, each of the flow rates of the first, second, and third pumps (101, 201, 301) can be controlled independently by performing the load sensing control, and in a combined operation for driving a boom (511) and an arm (512), ether one of them is driven by the first pump while the other one is driven by the second pump, and the swing is driven by the third pump. In the traveling operation, the maximum capacity of the first and second pumps is switched to the maximum capacity for the traveling operation and driven by an open center circuit. In a combined operation of traveling and the front implement, the front implement is driven by performing the load sensing control using the third pump.

Several hydraulic drive systems have been proposed for a work machine such as a hydraulic excavator. These hydraulic drive systems each include a plurality of main pumps, and perform load sensing control of at least one of the plurality of main pumps to achieve both excellent combined operability and energy saving.
For example, Patent Document 1 proposes a following structure.
A hydraulic drive system of a work machine such as a hydraulic excavator includes first and second pumps constituted by two delivery ports of a split flow type pump of a variable displacement type, and a third pump of a fixed displacement type. During non-traveling operation, the hydraulic drive system combines hydraulic fluids of the first and second pumps, and supplies the fluids to a front implement actuator to perform load sensing control. During swing operation, the hydraulic drive system supplies a hydraulic fluid of the third pump of the fixed displacement type to a swing motor via an open center circuit. In case of an operation for traveling only, or a simultaneous operation for operating actuators other than the front implement, such as operation for traveling and swing, the hydraulic fluids of the first and second pumps are supplied to left and right traveling motors via the open center circuit, while the hydraulic fluid of the third pump is supplied to the swing motor via the open center circuit. In case of a combined operation for traveling and the front implement, the hydraulic fluids of the first and second pumps are supplied to the left and right traveling motors, while the hydraulic fluid of the third pump is supplied to the front implement actuators. The hydraulic fluids in the combined operation are supplied via corresponding pressure compensating valves and flow control valves to perform split flow control using the pressure compensating valves.
Patent Document 2 proposes a following structure.
A hydraulic drive system of a work machine such as a hydraulic excavator includes first and second pumps constituted by two delivery ports of a split flow type pump of a variable displacement type, and a third pump of a variable displacement type. Each of the first and second pumps and the third pump is configured to perform load sensing control. Torque of the third pump is detected by approximation using two pressure reducing valves, and fed back to the first and second pumps. A hydraulic fluid of the third pump is used for main driving of a boom cylinder, while a hydraulic fluid of the first pump is used for assist driving of the boom cylinder. A hydraulic fluid of the second pump is used for main driving of an arm cylinder, while a hydraulic fluid of the first pump is used for assist driving of the arm cylinder.

Hibachi Construction Machinery Tierra Co., Ltd.


A method for continuously annealing aluminum alloy sheet at final thickness by continuously moving heat-treatable AlMgSi aluminum alloy sheet through a continuous annealing furnace arranged to heat the moving aluminum sheet to a set soaking temperature (TSET) in the temperature range of 500° C. to 590° C., the continuous annealing furnace has an entry section and an exit section, the moving aluminum sheet moves substantially horizontally through the continuous annealing furnace, wherein the moving aluminum sheet is rapidly cooled on leaving the exit section, wherein before or near the entry section of the continuous annealing furnace the moving aluminum sheet is pre-heated to a temperature of 5° C. to 100° C. below the TSET using an average heat-up rate as function of sheet thickness of at least Y=−31·ln(X)+50, wherein Y is the heat-up rate in ° C./sec and X is the sheet thickness in mm.

As will be appreciated herein below, except as otherwise indicated, aluminium alloy designations and temper designations refer to the Aluminum Association designations in Aluminum Standards and Data and the Registration Records, as published by the Aluminum Association in 2014 and well known to the persons skilled in the art.
The industrial scale automotive sheet production of the heat-treatable AlMgSi-alloy series, also known as 6000-series aluminium alloys, typical examples include AA6005, AA6014, AA6016 and AA6022, comprises several discrete steps, namely semi-continuous direct chill (DC)-casting or electromagnetic casting (EMC-casting) of a rolling slab or ingot, although on a less preferred basis also continuous casting like belt or roll casting can be applied, preheating of the slab at about 500° C. to 580° C. for several hours for homogenization of the microstructure, hot rolling into hot rolled strip at a gauge of about 3 to 12 mm, the hot rolled strip is typically hot coiled and cooled down to ambient temperature, the hot rolled strip is cold rolled to final gauge in several passes, optionally an intermediate anneal is applied prior to the cold rolling or during the cold rolling process, and at final gauge the strip is annealed to adjust the required material properties. The annealing can be done either in a continuous annealing furnace or in a batch type furnace.
Unfortunately, sheet products produced in this way from semi-continuous cast ingots often suffer from a phenomenon known as roping, ridging or "paint brush" line formation (the term "roping" is used henceforth), i.e. the formation of narrow bands having a different crystallographic structure than the remaining metal resulting from the metal rolling operation and generally aligned in the direction of rolling. During subsequent transverse straining of the sheet products as they are being formed into automotive parts, these bands manifest themselves as visible surface undulations, which detract from the final surface finish of the automotive product.
Roping has been encountered by many others in this art, and it has been found that roping may be inhibited by modifying the sheet production method so that recrystallisation occurs at an intermediate stage of processing. The inhibition of roping is addressed, for example, in U.S. Pat. No. 5,480,498 (Reynolds), U.S. Pat. No. 4,897,124 (Sky Aluminum), and also in U.S. Pat. No. 6,120,623 (Alcan). In these patents, roping is controlled by introducing a batch annealing step (e.g. heating at a temperature within the range of 316° C. to 538° C.) at an intermediate stage of the sheet product formation, e.g. after hot rolling but before cold rolling, or after an early stage of cold rolling.
An economical attractive method of producing 6000-series aluminium sheet material is by means of continuous annealing at final gauge. At the end of a continuous annealing furnace, the strip material is rapidly cooled or quenched to ambient temperature, for example by means of forced air cooling or spray cooling systems. By this solution anneal the main alloying elements Mg and Si are dissolved, leading to a good formability, control of the yield strength and bake hardening behaviour, and brings the sheet material to a T4 temper.
In order to produce AlMgSi-alloy sheet material on an industrial scale in an economical attractive manner, it is required that sufficiently high line speeds can be maintained while the sheet material is moving through the continuous annealing furnace. However, too high line speeds may impact on the soaking time of the strip material at the required annealing temperature and thereby affecting, amongst others, the mechanical properties of the aluminium strip.
There is consequently a need for an improved process of producing aluminium automotive alloy sheet products that exhibit little or no roping while maintaining desirable T4 characteristics.

Method of annealing aluminium alloy sheet material


A method, apparatus and product performing feature vector aggregation for malware detection. Two sets of measurements produced by a two dynamic analyses of an examined program are obtained, wherein the two dynamic analyses are performed with respect to the examined program executing two different execution paths. An aggregated feature vector representing the examined program is generated. The aggregated feature vector comprises a set of aggregated features, wherein a value of each aggregated feature is based on an aggregation of corresponding measurements in the first set of measurements and in the second set of measurements. A predictive model is applied on the aggregated feature vector to classify the examined program as malicious or benign.

Proliferation of malware poses a major threat to modern computerized system of all sizes and shapes. Malware has evolved into a powerful instrument for illegal commercial activity, and significant effort is made by its authors to thwart detection by anti-malware products. Malware is used in fraud, espionage, and in other illegal activities. The malware penetrates the computerized system by exploiting its vulnerabilities, or the vulnerabilities of the people operating it. After the malware has penetrated the system, it may attempt to manipulate data, retrieve confidential information, activate malicious functionalities, or the like.
As a result, malware detection is an important branch of cyber security of every system. One long prevailing technique of malware detection is based on manual identification of malware and extraction of identifiable signatures to be used to identify the same malware on different systems. Such solution relies heavily on expert knowledge and on the ability of human experts to manually inspect software, and is thus not scalable.

Feature vector aggregation for malware detection

International Business Machines Corporation


A method for treating a tumor by combining a piperidine compound of formula (I) or salt thereof and a microtubule-targeting drug, in which the microtubule-targeting drug is administered once per 7 days or more one cycle, and the piperidine compound is administered once or more per day for 4 days or more:

Aurora A is a serine/threonine kinase. It is reported that Aurora A is involved in e.g., formation and maturation of a centrosome, spindle kinetics and chromosome alignment in the mitotic phase (M phase) of the cell cycle and regulates a process of mitotic division (Non Patent Document 1). Up to present, it has been confirmed that Aurora A is excessively expressed and/or amplified in a wide variety of types of carcinomas (Non Patent Document 2). Furthermore, inhibition of Aurora A kinase in a tumor cell induces arrest of mitotic division and induction of apoptosis. Thus, Aurora A is an important target molecule for cancer treatment.
Microtubule-targeting drugs such as taxane antitumor agents and vinca alkaloids have been widely used as cancer chemotherapeutic agents. However, due to refractoriness and resistance to these agents, sufficient therapeutic effects are not sometimes obtained. Thus, it is expected that an agent capable of enhancing the antitumor effect of a taxane antitumor agent can more effectively treat cancer. In the cytotoxicity reaction of a taxane antitumor agent, it is required to activate a spindle assembly checkpoint in a cell cycle. In tumor cells reduced in this activity, sensitivity to a taxane antitumor agent decreases (Non Patent Document 3), in addition, a cell strain, in which Aurora A is excessively expressed, develops resistance to paclitaxel (Non Patent Document 4). Thus, it has been reported that an effect of paclitaxel or docetaxel is enhanced if Aurora A is inhibited (Non Patent Document 5).
In the meantime, Aurora B, which is a subtype of Aurora A, acts on the mitotic phase (M phase) of the cell cycle similarly to Aurora A. However, it has been reported that if Aurora B is inhibited, the activity of a spindle checkpoint is reduced (Non Patent Document 6). Thus, there is a possibility that inhibition of Aurora B may attenuate the effect of a taxane antitumor agent. From the descriptions above, it is expected that if an agent selectively inhibiting Aurora A kinase is used in combination with a taxane antitumor agent, its antitumor effect can be enhanced to produce a higher therapeutic effect.
Under the above circumstance, MK-5108 is reported as an Aurora A selective inhibitor (Non Patent Document 7). In this document, an antitumor effect is evaluated by administering MK-5108 and docetaxel to nude rats. To describe it more specifically, docetaxel is administered and then, 24 hours later, MK-5108 is orally administered twice per day over 2 days. Although enhancement of an antitumor effect is confirmed, its therapeutic effect is not sufficient.

Method for enhancing anti-tumor effect of a microtubule-targeting drug, and a method for treatment of tumor

Abstract: R1 represents a carboxyl group, —C(═O)NR5R6, or an oxadiazolyl group optionally substituted with a C1-C6 alkyl group or trifluoromethyl group;        R2 represents a halogen atom or C1-C6 alkoxy group;        R3 represents a phenyl group optionally having 1 to 3 groups, selected from a halogen atom, and a C1-C6 alkyl, C1-C6 alkoxy, or trifluoromethyl group;        R4 represents a hydrogen atom or C1-C6 alkyl group; and        R5 and R6, each represent a hydrogen atom, a C1-C6 alkyl or C3-C6 cycloalkyl group; or R5 and R6, together with a nitrogen atom, optionally form a 3 to 6-membered nitrogen-containing saturated heterocyclic group.


A method and structure for fabricating a dual damascene copper interconnect which electrically contacts a damascene tungsten wiring level. The method forms a first layer on a semiconductor substrate, a silicon nitride layer on the first layer, and a silicon dioxide layer on the silicon nitride layer. The first layer includes damascene tungsten interconnect regions separated by insulative dielectric material. A continuous space is formed by etching two contact troughs through the silicon dioxide and silicon nitride layers to expose damascene tungsten interconnect regions, and by etching a top portion of the silicon dioxide layer between the two contact troughs. A reduced-height portion of the silicon dioxide layer remains between the two contact troughs. The continuous space is filled with damascene copper. The resulting dual damascene copper interconnect electrically contacts the exposed damascene tungsten interconnect regions.

1. Technical Field
The present invention relates to a method and structure for fabricating a dual damascene copper wiring interconnect contacting a damascene tungsten wiring level.
2. Related Art
An integrated circuit fabricated on a semiconductor substrate typically requires multiple levels of metal interconnections for electrically interconnecting discrete semiconductor devices on the semiconductor substrate. A lower wiring level of damascene tungsten contacts is commonly used to provide local interconnections between the semiconductor devices which exist within and upon the substrate layer. Unfortunately, it is problematic to generate reliable, low resistance contacts between an upper level of damascene copper wiring and the lower wiring level of damascene tungsten contacts.
There is a need for a method and structure that generates reliable, low resistance contacts between an upper level of damascene copper wiring and the lower wiring level of damascene tungsten contacts.
The present invention presents a method for fabricating an electronic structure, said method comprising the steps of:
providing a wafer having a semiconductor substrate;
forming a first layer on the semiconductor substrate, wherein the first layer includes a plurality of electrically conducting regions, wherein each electrically conductive region includes an electrically conductive material selected from the group consisting of tungsten and silicon, and wherein the electrically conducting regions are separated by insulative dielectric material;
forming an etch stop layer over the first layer, wherein the etch stop layer includes an etch stop insulative material;
forming an insulator layer over the etch stop layer, wherein the insulator layer includes an electrically insulative material;
forming a plurality of contact vias extending through the insulator layer down to the etch stop layer and over corresponding electrically conducting regions such that there is not substantial rounding of the corners at the top of the reduced height portion of the insulator layer;
etching a top portion of the insulator layer adjacent each contact via, leaving a reduced-height portion of the insulator layer adjacent each contact via such that a continuous space is formed, wherein the continuous space includes each contact via and a space above the reduced-height portion of the insulator layer;
etching the etch stop layer at the bottom of each contact via, which exposes top surfaces of the corresponding electrically conducting regions below each contact via; and
filling the continuous space with a refractory metal liner and damascene copper such that a damascene copper interconnect is formed within the continuous space, wherein the damascene copper interconnect is in electrically conductive contact with the top portions of the electrically conducting region.
The present invention provides an electronic structure, comprising:
a semiconductor substrate;
a first layer on the semiconductor substrate, wherein the first layer includes a plurality of electrically conducting regions, wherein the electrically conductive regions each include an electrically conductive material selected from the group consisting of tungsten and silicon, and wherein the electrically conducting regions are separated by insulative material;
a damascene copper interconnect wiring level having a plurality of damascene copper wires within one or more corresponding damascene contact vias wherein each damascene copper wire is in electrically conductive contact with a corresponding conducting region of the electrically conducting regions;
an etch stop layer on the first layer, wherein each etch stop layer does not exist where the damascene contact via exists, and wherein the etch stop layer includes an etch stop insulative material;
a first insulator region of an insulator layer on a first portion of the etch stop layer and contacting a first surface of the damascene copper interconnect, wherein the first insulator region includes an electrically insulative material;
a second insulator region of the insulator layer on a second portion of the etch stop layer and contacting a second surface of the damascene copper interconnect, wherein the second insulator region includes the electrically insulative material; and
a third insulator region on a third portion of the etch stop layer and disposed between the damascene copper interconnect and the third portion of the etch stop layer, wherein the second insulator region includes the electrically insulative material.
The present invention provides a method of cleaning a surface of a volume of material, comprising the steps of:
providing the volume of material, wherein the material includes a refractory metal or silicon; and
acid cleaning with hydrofluoric acid the surface of the volume of material.
The present invention further provides a method for fabricating an electronic structure, said method comprising the steps of:
providing a wafer having a semiconductor substrate;
forming a first layer on the semiconductor substrate, wherein the first layer includes a plurality of electrically conducting regions, wherein each electrically conductive region includes an electrically conductive material selected from the group consisting of tungsten and silicon, and wherein the electrically conducting regions are separated by insulative material;
forming an etch stop layer over the first layer, wherein the etch stop layer includes an etch stop insulative material;
forming an insulator layer over the etch stop layer, wherein the insulator layer includes an electrically insulative material;
forming a contact via extending through the insulator layer down to the etch stop layer and over a corresponding electrically conducting region such that there is not substantial rounding of the corners at the top of the reduced height portion of the insulator layer;
etching the etch stop layer at the bottom of the contact via, which exposes the top surface of the corresponding electrically conducting region below the contact via; and
filling the contact via with a refractory metal liner and damascene copper such that a damascene copper interconnect is formed within the contact via, wherein the damascene copper interconnect is in electrically conductive contact with the top portion of the electrically conducting region.
The present invention therefore provides a method and structure that generates reliable, low resistance contacts between an upper level of damascene copper wiring and the lower wiring level of damascene tungsten contacts.

Dual damascene copper interconnect to a damascene tungsten wiring level

International Business Machines Corporation


A method for encapsulating semiconductor devices includes the steps of: providing a molding system and a close-loop control system which is coupled to the molding system, the close-loop control system including a computer, a programmable logic control, a servo motor controller, and at least two drivers, wherein the servo motor controller is coupled to the computer and the programmable logic control, respectively, the servo motor controller is further coupled to the drivers, and the drivers are coupled to the molding system; clamping together at least one set of top and bottom molds of the molding system, the molding system including a clamping assembly having a clamping axis, the close-loop control system being coupled to the clamping assembly; feeding a molding compound into a cavity formed by a space between at least one set of top and bottom molds, the molding system further including a transfer assembly having a transfer axis; alternating a gear switching assembly of the molding system between a high speed mode and a high torque mode along the clamping axis, the gear switching assembly being coupled to the clamping assembly; and providing feedback from the close-loop control system to the clamping assembly and transfer assembly of the molding system to minimize disproportionate drive along the clamping and transfer axes, respectively.

1. Field of the Invention
The present invention relates to a method and apparatus for encapsulating semiconductor devices in an automatic molding system which complies with the high volume output requirement for semiconductor manufacturing. In particular, the present invention pertains to a direct drive electra-mechanical press for encapsulating semiconductor devices in a clean room environment which is ideal for In-line semiconductor manufacturing systems. By in-line manufacturing systems, the present invention refers to systems where all the machines necessary for producing the end product are laid out in a line, thus minimizing the transportation and handling of the product which is in process between machines.
2. Description of the Related Art
Traditionally encapsulation of semiconductor devices is accomplished by using a transfer hold tool mounted onto a press. The press serves two functions: (1) the press provides the clamping tonnage to clamp the molds together in order to prevent bleeding and flashing of the resin during the encapsulation process, and (2) the press provides the transfer action to transfer the molding resin compound into the mold cavities. The presses used for molding semiconductor devices in the encapsulation process are hydraulic based. Examples of hydraulic presses Include U.S. Pat. No. 4,599,062 and Japan Patent No. J5 9204-244-A.
The main disadvantages of a hydraulic transfer press are the contaminations from hydraulic leakages and oil fumes generated from the hydraulic pump system. As a result, the molding operation using a hydraulic press has to be isolated from the front-end of the encapsulation process which involves die attach, wire bonding and etc. because those operations are performed in a clean room environment.
As semiconductor fabrication operations are moving towards in-line systems, it is essential to integrate various processes including the molding operation in a clean room environment. An electro-mechanical press using a toggle mechanism has been developed recently to overcome the problems encountered during the molding process using a hydraulic press.
While the electro-mechanical press for encapsulating semiconductor devices overcomes the problems of the prior art systems featuring a hydraulic press. It has two major disadvantages: high wear at the joints, and disproportionate drive control.
The toggle mechanism used in an electro-mechanical press consists of a plurality of linkages and joints. In semiconductor encapsulation process under an in-line system, the linkages and joints experience high rate of wear and tear. As such, frequent maintenance and down time are incurred to prevent the failure of the total system.
The toggle mechanism in an electro-mechanical press relies on the principles of mechanical advantage. It follows that the output from the servo motor is used as an input to the plurality of linkages and joints. The disadvantage of the toggle mechanism lies in the disproportionate amplification of the Input to the linkages and joints. In other words, the amplified output of the servo motor from the toggle mechanism is not constant. The magnitude of amplification depends on the angles between the output links and the input links. In a typical press for encapsulating semiconductor devices, there are at least four links called the tie bars. The amplification factors increase exponentially during the last phase of clamping. As a result, the disproportionate amplification of the servo motor output can either over-clamp or break the tie bars.
The present invention comprises a direct drive electro-mechanical press for encapsulating semiconductor devices. The press has at least two axes--a clamping axis and a transfer axis. The clamping axis comprises a first planetary roller screw coupled to a tie bar platen assembly on which at least one top mold is mounted. A two-speed gearbox is further coupled to the clamping axis for switching between a high speed mode and a high torque mode along the clamping axis. The two-speed gearbox comprises a high speed clutch coupled to a speed reducer and a high torque clutch respectively. The transfer axis is slidably located above the clamping axis; the transfer axis comprises a second planetary roller screw coupled to a central platen on which at least one bottom mold is mounted. The transfer axis transfers the molding resin from the pot into the cavities formed when the top and bottom molds ere clamped together. The use of two-speed gearbox and the first planetary roller screw along the clamping axis and the use of the second planetary roller screw along the transfer axis not only reduce the number of joints or links required under prior art systems, but also permit the press to deliver superior velocities and clamping tonnage.
A closed-loop control is provided to the clamping and transfer axes respectively for minimizing the disproportionate drive from the electro-mechanical press. In addition to the controllers and drivers, the closed-loop control provide direct feedback on the clamping tonnage on the tie bars and transfer pressure In the mold blocks. While better system control is achieved, problems associated with disproportionate drive from the servo motors such as breakdown due to over-clamping are minimized.

Method of encapsulating semiconductor devices by a direct drive electro-mechanical press


A level detection circuit includes a multiplier and an adder for computing the sums of square values of a burst signal. A maximum value holding circuit holds a maximum value of the sums of the squared values of the burst signal. A counter counts sampling clocks. A multiplier, an adder and a 1/2 processing circuit compute a half value of the sum of two consecutive count values, and a delay circuit, a latch circuit and a comparator generate a first one of the two consecutive count values as a level of the burst signal when an output of the 1/2 processing circuit becomes larger than the output of the maximum value holding circuit. The invention enables level detection by finding a square value using a small circuit.

This invention relates to a level detection circuit for detecting the signal level of input signals and, more particularly, to such a circuit employed in an automatic color saturation control (ACC).
A television receiver or the video tape recorded, for example, is provided with an automatic Color saturation control (ACC) circuit. In the television receiver, if the level difference between luminance signals and the carrier chrominance signals fluctuates because for example of fluctuations in the received electrical waves or mismatching of an antenna system, saturation on a display screen is changed in an irregular manner. Besides, solely the color saturation may be changed by channel switching. Consequently, the aforementioned ACC circuit is built into the television receiver for automatically adjusting the gain of the bandwidth amplifying circuit which is operated for maintaining a constant level of the carrier chrominance signals applied to a demodulation circuit. The ACC circuit, which compares a burst amplitude value to a reference value for controlling the gain for maintaining the color saturation at all times at a constant level, is arranged as shown for example in FIG. 1.
In this figure, carrier chrominance signals are supplied to an input terminal 21 of the ACC circuit and thence supplied to a level detection circuit 25 via a multiplier 23. The level detection circuit 25 detects the level of the carrier chrominance signals. Since the chroma level is determined by the level of a burst signal, the level detection circuit 25 detects the level of the carrier chrominance signal, that is the burst amplitude, when a burst gate pulse supplied via terminal 22 from a sync deflection block of the television receiver is at e.g. a high "H" level.
The ACC circuit decides a loop gain by integrating the difference between the level detection output from the level detection circuit 25 and a reference. That is, with the present ACC circuit, the level detection outpost of the level detection circuit 25 is supplied as an additive signal to an additive node 26 also supplied with a predetermined reference value as a subtractive signal from a level reference value generating circuit 28. A difference output between the level reference value and the level detection output is produced by the additive node 26 so as to be supplied to an integrating circuit 27. An integrated output of the integrating circuit 27 is supplied as a multiplication coefficient to the multiplier 23. The carrier chrominance signal from multiplier 22 is multiplied by the multiplication coefficient from the integrating circuit 27. A multiplication signal from multiplier 23 is outputted as ACC output at an output terminal 24 so as to be supplied to a downstream decoder, not shown.
The aforementioned burst gate pulse is generated in the following manner. For example, horizontal synchronization signal H.sub.SY is extracted from a composite video signal shown in FIG. 2, by a sync separator, not shown, provided within the deflection system. The horizontal synchronization signal H.sub.SY is differentiated, as shown in FIG. 3, and a rising part of the differentiated waveform is cut along a threshold value V.sub.TH for producing the aforementioned burst gate pulse which is a pulse having a position corresponding to the burst, period.
Meanwhile, in the above-mentioned level detection circuit 25, shown in FIG. 1, a square root value is found for finding the burst amplitude of the color chrominance signals. Typical of the prior-art arrangements for finding the square root is an arrangement employing a read-only memory (ROM).
However, if higher precision in square root calculation is desired in the arrangement for finding the square root by ROM, the number of address bits of ROM and the number of bits of data stored in ROM are increased so that a ROM of larger capacity is required and hence the circuit is undesirably increased in size.

Level detection circuit and ACC circuit employing the level detection circuit


High-density polyisocyanurate resins having improved rigidity, heat resistance and/or impact resistance can be obtained by reacting a polyisocyanate with a polymer polyol derived from a polyol having a molecular weight of at least 4500, and optionally a crosslinker, in the presence of trimerization catalyst, using isocyanate index of 200-5000.

1. Field of the Invention:
This invention relates to polyisocyanurate resins. More particularly, it relates to high-density polyisocyanurate resins having improved properties such as rigidity, high-temperature properties, impact resistance and curing characteristics, and a process of making the same.
2. Description of the Prior Art:
It has been known that polyisocyanurate foams have good heat resistance and flame resistance. It has also been proposed to produce such polyisocyanurate foams with heat-resistant heterocyclic structures formed by cyclization of grafted side-chain acrylonitrile groups, using polymer polyols (acrylonitrile-grafted polyetherpolyols). However these foams are high-expanded, and brittle and not high-impact, and their heat resistance and rigidity are not fully satisfied.

Polyisocyanurate resin and process for making the same


The basic component of the output ESD protection circuit of the present invention comprises a low resistance connected in series between an output pad and conventional active output pad pullup and pulldown drivers. In a preferred embodiment, a polysilicon resistor is connected in series between an output pad and a metal bus. On the metal bus, a lateral bipolar device is connected in parallel to an n-channel pulldown at an output node and a common potential (conventionally labeled as V.sub.SS). The pullup device is also an active n-channel pullup device connected between an operating potential (conventionally labeled as V.sub.CC) and the output node. Both drains of the two n-channel devices have n-well underneath the n+ diffusion in the area where metal contacts are formed to thereby prevent metal spiking to the substrate during an ESD event. This circuitry combination provides ESD protection equal to or greater than the voltage range of +8000/-2000 V for the HBM response (the Mil. Std. human body model [HBM] test model) as well as protection equal to or greater than the voltage range of +900/-700 V for the MM EIAJ response (the EIAJ machine model [MM] test model). The concept of using a low resistance between a pad and associated active devices (i.e., ESD protection circuitry) will work in combination with other ESD protection circuitry layouts and work equally well for input pad ESD protection.

Increasing pin counts, as well as faster circuit speeds, have compounded the need for reliable ESD protection in integrated circuits (ICs). Input/output signals to a complimentary metal oxide semiconductor (CMOS) circuit are typically fed to input/output pads which are connected to the gates of metal oxide semiconductor (MOS) transistors. If high static discharge voltage is accidently applied to any of the input/output pins of an IC, the input/output transistor's gate insulator and the contacts between the pad and the underlying active area are vulnerable to damage if adequate ESD protection is not present. Therefore, all pins of MOS ICs must be ESD protected to prevent any harmful static discharge voltages from damaging the IC.
Four main types of ESD protection circuits have been implemented in IC design which are intended to provide a current path to ground to absorb the high static discharge voltage. These four main ESD protection circuits include: 1) diode breakdown, 2) node-to-node punchthrough, 3) gate-field-induced breakdown, and 4) parasitic pnpn diode latchup.
Operation and construction of each of the four main types of ESD protection circuits have been described in various publications, such as the textbook "SILICON PROCESSING FOR THE VLSI ERA"--VOLUME II, 1990, pp. 442-446 and therefore are not described further herein.
Also, an output ESD protection circuit is described in an article entitled "OUTPUT ESD PROTECTION TECHNIQUES FOR ADVANCED CMOS PROCESSES", C. Duvvury et al., 1988 EOS/ESD SYMPOSIUM PROCEEDINGS, pp. 206-211.
This article describes a buried n+ (BN+) diffusion output device structure for an output ESD protection circuit for advanced CMOS processes (specifically in dynamic random access memories--DRAMs). According to this article, the BN+ devices can be incorporated into both pull-up and pull-down output devices with adequate drive currents and no transconductance degradation. However, as the article points out, there might be a concern about the devices' hot electron reliability due to reduced channel length and possible extra trap centers introduced by the BN+ process.
Though the output circuit mentioned above provides reasonable ESD protection, its possible that inherent problems may not deem this structure as being desirable. The output ESD protection circuit of the present invention allows ESD protection equal to or greater than the voltage range of +8000/-2000 V for the HBM response (the Mil. Std. human body model [HBM] test model) as well as protection equal to or greater than the voltage range of +900/-700 V for the MM EIAJ response (the EIAJ machine model [MM] test model) due to its' unique and yet simplistic fabrication layout.
All publications cited herein are hereby incorporated by reference.