Short and long wavelength absorption losses contribute to loss at the operating wavelength of an optical fiber drawn from a preform. Excess losses over and above Rayleigh scattering losses have been attributed to conditions such as temperature and the speed during drawing. Typically, after optical fiber (21) is drawn from an optical preform in a furnace (23) wherein temperatures may be 2200.degree. C. or higher, the fiber is moved out of the furnace and immediately through ambient environment to other portions of a draw line such as, for example, measuring and coating apparatus. It has been found that these absorption losses may be reduced substantially by application of a magnetic field to the optical fiber after it has been drawn and prior to it being coated.

Optical communications systems, that is systems operating in the visible or near visible spectra, are now at an advanced state of development. Such systems utilize glass fibers as the transmission medium. These fibers, generally having an overall cross-sectional diameter of about 125 .mu.m, are generally composed of at least two portions, a central core and a cladding layer disposed about the core. The cladding layer has an index of refraction which is less than that of the core, with a typical index variation from the core to the cladding layer being in the range from about 0.01 to 0.05. Optical fibers in use may be single-mode or multimode. The former is characterized by a sufficiently small core to accommodate efficiently only the first order mode. Such single-mode optical structures may have a core diameter of about 8 .mu.m. Multimode optical fibers typically have cores which have a diameter in the range of about 50 .mu.m to 100 .mu.m.
In the manufacture of optical fiber, a glass preform rod which generally is manufactured in a separate process is suspended vertically and moved into a furnace at a controlled rate. The preform rod softens in the furnace and optical fiber is drawn freely from a molten end of the preform rod by a capstan located at the base of a draw tower. Because the surface of the optical fiber is very susceptible to damage caused by abrasion, it becomes necessary to coat the optical fiber, after it is drawn, but before it comes into contact with any surface.
One of the most important parameters for an optical fiber is loss. Loss which is expressed in decibels per kilometer (dB/Km) can be caused by absorption of impurities in the glass, or by scattering of the light. Production optical fibers are made of glass which contains impurities, as well as compositional variations. Optical loss can be plotted as a function of the wavelength of light passing through the optical fiber. For silica fibers doped with germanium and/or phosphorus, there is a minimum loss at a wavelength of about 1.55 .mu.m. The selection of doped silica glass takes advantage of the "window" between infrared molecular vibration absorption and Rayleigh scattering plus ultraviolet absorption regions or "tails".
Rayleigh scattering results from density and compositional variations within the fiber material. Rayleigh scattered energy is absorbed in the cladding and guided in a backward direction. During the processing of optical fiber, it is desired to reduce the impurity absorption loss to zero so that only the loss due to Rayleigh scattering remains. However, other forms of scatter loss may occur and impede the achievement of this goal. One is loss caused by variations in the size of the fiber core. Dimensional variations introduced into production fiber can cause loss by light scattering and influence the quality of a fiber connector or splice because of size differences.
Absorption results when light photons contain sufficient energy to excite electrons of the glass constituent materials. In transparent media of pure silica, the oxygen atoms have very tightly bound electrons and only ultraviolet light photons have enough energy to be absorbed. However, the silica in optical fiber includes dopants and transition-metal impurities whose electrons can be excited by lower energy light. Those constituents cause the ultraviolet absorption to be shifted lower and cause additional absorption bands in the visible and near infrared ranges. The amount of loss which is caused by the presence of these impurities depends on their concentration. At certain wavelengths, relatively small concentrations of impurities may cause an increase in absorption loss of about 1 dB/Km.
In addition to the problem of impurity absorption, another problem arises from the presence of the hydroxyl (OH.sup.-) ion. The fundamental vibration of this ion occurs at a wavelength of 2.7 .mu.m, but overtones at 0.95 and 1.4 .mu.m extend to the priorly mentioned window region. Concentrations of OH.sup.- as low as one part per million can cause losses as high as 1 dB/Km at 0.95 .mu.m and 50 dB/Km at 1.4 .mu.m. Obviously, it is important to reduce these so-called water peaks to as low a value as possible to achieve the lowest loss in transmission windows around 1.3 .mu.m and 1.55 .mu.m.
Low loss silica-rich fibers are made by using silicon tetrachloride (SiCl.sub.4) as a precursor material. This material typically is very low in transition-metal ion impurities, but may contain substantial amounts of hydrogen-bearing compounds. Because the glass for the fiber is formed in a process by reacting the SiCl.sub.4 with oxygen, OH.sup.- can form readily if hydrogen is present. Hence, it is important not only to use precursor materials that are low in hydrogen content, but also to prevent entry of similar compositions into the process or inadvertent contamination by handling.
Optical fiber loss also has been found to depend on conditions during the drawing of the fiber from a preform such as, for example, the temperature of the preform during draw, and the speed at which the fiber is drawn. These last two mentioned conditions also determine the fiber tension during draw. During the drawing of the optical fiber, defects are generated and the number of defects is dependent on the drawing conditions which of course can cause changes in the loss. However, these defects seemingly are rendered benign if the preform from which the optical fiber is being drawn includes alkalies.
Although the presence of alkalies is helpful in rendering impotent those defects caused during drawing, another problem concerning absorption losses revolves around the use of precursor tubes, the composition of which includes relatively low levels, i.e. about 100 to 0.1 ppm atomic, of alkalies. It has been found that the long term hydrogen effect attributed to the presence of alkalies affects adversely the performance of the optical fiber drawn from a preform which has been manufactured from such a precursor tube. This problem becomes particularly acute when using a so-called rod and tube process in which a preform rod is overclad with a tube to provide a larger preform for draw. During the processing of a substrate tube which includes alkalies in a normal MCVD process, for example, the alkali level somehow is reduced. In the rod and tube process, which is today becoming very popular as a means to save costs, this does not occur and long term hydrogen-related absorption losses will increase.
Because of such adverse effects, efforts have been made to provide precursor quartz tubes which are substantially alkali-free. It has been found that absorption losses which have been somewhat troublesome in the past may increase substantially when using alkali-free precursor tubes.
What were needed were methods and apparatus which provide an optical fiber having relatively low drawing-induced absorption losses. A method of making an optical fiber having a relatively low absorption loss includes the step of moving an optical preform incrementally into a device in which the preform is exposed to heat energy and then drawing optical fiber from each successive portion of the preform as it is exposed to the heat energy. Then the temperature of the drawn fiber is caused to decrease in a controlled manner which causes the absorption loss of the drawn fiber to be relatively low. In a preferred embodiment, the temperature of the drawn optical fiber is caused to decrease gradually to avoid an abrupt change in that parameter which has been commonplace in the prior art. This may be accomplished, for example, by appending a recovery tube to a lower end of a draw furnace or by engaging the drawn optical fiber with a gas at a controlled temperature or both to anneal the drawn fiber in a controlled manner.
It should be apparent that the use of a recovery tube to anneal defects is line speed limited and that to achieve the best results, the line speed needs to be on the low end of the scale. This, of course, is counterproductive to recent efforts to increase line speed. Higher line speeds are achievable because of improved optical fiber coating techniques, but the annealing step remains line speed limiting.
What is sought after and seemingly what is not available in the prior art are methods and apparatus for annealing drawn optical fiber to reduce loss without limiting the speed at which the optical fiber is moved along a drawing line. Such sought after methods and apparatus should be capable of being integrated easily into existing optical fiber draw lines or towers as they commonly are called.

Methods and apparatus for increasing optical fiber draw speed


A signal carrying cable in which the return, negative or cold conductor is greater in overall cross sectional area and mass than the signal, positive or hot conductor, based on a specific ratio that balances the flow of electrons, enhances electron movement and as a result improves signal transmission. The ratio is based firstly on the cross sectional area of each signal core/s in relation to each return core/s, and secondly on the diameter or perimeter of each signal strand in relation to each return strand. The ratio works effectively whether there are one or more strands in each conductor. For cables where the diameter or perimeter of each strand is the same for both signal and return, the ratio is based on cross sectional area only. Cables can comprise conductor strands other than round i.e. square, flat, rectangular, tubular etc.

This invention relates to an improvement in the handling of reactance, improved electron flow balance, enhanced electron movement and subsequent improved performance in a signal carrying cable design to be used, for example, as an interconnect cable with phono or RCA type plug termination (connecting two pieces of electronic equipment such as CD or DVD player to pre-amplifier, pre-amplifier to amplifier etc) and loudspeaker cable (connecting amplifier to loudspeaker) for audio and home theatre applications. The invention is also effective for other cable applications such as data communication cables, microphone leads, patch cords and the like, video and digital cables, and any other signal carrying cables. Furthermore the invention can be used effectively for copper traces for circuit boards and in some signal carrying connecting hardware such as RCA type phono plugs and sockets, RF or coaxial connectors, and spade connectors wherever a signal and return conductor are involved.
As such, this invention has particular but not exclusive application to signal carrying cables, and for illustrative purpose reference will be made to such application.
Many signal carrying cable products are expensive, complex designs that are difficult to manufacture.
The complexity of the cable designs come about as designers seek to electrically optimize cables by reducing distortion and coloration to a minimal level. Two types of distortion that are recognized as being problematic are inductive reactance and capacitive reactance.
Variable current flow in a conductor generates inductance and capacitance as well as inductive reactance and capacitive reactance. Inductive reactance is directly proportional to frequency. So, when frequency increases, inductive reactance also increases. Capacitive reactance is inversely proportional to frequency. In other words, as frequency increases, capacitive reactance decreases.
In a signal carrying cable where the signal and return have the same strand number, strand size and mass, the overall inductive and capacitive reactance characteristics are increased (i.e. a doubling effect where reactance in the signal is combined with the reactance in the return) and as such the reactive resistance to each frequency is not balanced.
The present invention overcomes problems of reactance in signal carrying cables by speeding up the flow of electrons in the return conductor and balancing the reactive characteristics between signal and return. This is achieved by increasing the mass in the return conductor in relation to the mass of the signal conductor by using a specific ratio. When the mass of the return conductor is greater than the mass in the signal conductor the resistance of the return is significantly lower (than that of the signal) thereby providing a faster pathway for electrons to travel.
The return conductor is by its nature always responding to the signal conductor because it is constantly in delay mode. In the present invention the increased size and mass of the return conductor enables the return to respond more rapidly to the signal allowing an unimpeded and speedy flow of electrons.
By enhancing the flow of electrons in the cable, problems such as capacitive and inductive reactance appear to be diminished. A useful analogy is wind effect on a speeding bullet. The faster the bullet, the less influence wind has on its movement.
When using the ratio, the electron flow between signal and return conductors also appears more evenly balanced, with electrons at all frequencies travelling at the same apparent speed.
The ratio at the heart of the present invention is a ratio of firstly the cross sectional area of the signal core in relation to the return core, and secondly the diameter or perimeter of each electrically conductive strand in the signal in relation to the return, where the mass is intentionally increased in the return core.
The present invention relates to a cable with cores defined as the following:
1: A single strand within an insulated jacket hereinafter called xe2x80x9csolid corexe2x80x9d.
2: A multi-strand core comprising non-insulated strands grouped together within an insulated jacket hereinafter called xe2x80x9cmulti-strand corexe2x80x9d.
3: Multiple strands individually insulated which may be grouped together within an insulated jacket hereinafter called xe2x80x9cLitz style corexe2x80x9d.
4: Any of the above where the signal conductor core is shielded by a braided or foil shield as in a coaxial configuration, hereinafter called xe2x80x9cshielded corexe2x80x9d.
The ratio of cross sectional area of the total signal core in relation to the total return core for solid cores, multi-strand cores and Litz-style cores is between 1:2.6 and 1:4.0 with the preferred ratio being 1:2.778.
When using a shielded core, the preferred ratio of cross sectional area of the total signal core in relation to the total return core is 1:3.56.
The increase in preferred ratio used for a shielded core (for example coaxial style 75 Ohm or 110 Ohm video or digital cable) appears to be due to a capacitive and/or inductive effect caused by an interaction between signal conductor and the surrounding shield, and return conductor and the shield.
The preferred ratio may also increase or decrease as a result of various shielding configurations, insulation types and metal conductors that may be used or the combination thereof. For example heavier shielding and/or change of impedance between signal conductor and shield may change the ratio. Similarly the use of high purity silver conductors may require a slightly different ratio to Oxygen free copper (OFC) conductors.
The ratio of stranding size of individual solid strand/s within the signal core in relation to individual solid strand/s within the return core of solid cores, multi-strand cores and Litz-style cores, and based on the diameter or perimeter of each strand, is 1:1.6 to 1:2.0, with the preferred ratio being 1:1.667. When using a shielded core, the preferred ratio is 1:1.887.
The preferred signal carrying cable design is one that uses the cross sectional area ratio and the diameter or perimeter ratio together.
For cables comprising multi-strand cores or Litz style cores and where the diameter or perimeter of each individual strand is the same for both signal and return, the ratio is based on the cross sectional area between the signal and return core and is between 1:2.6 to 1:4.0 with the preferred ratio being 1:2.778. When using a shielded core, the preferred ratio is 1:3.56.
Using the ratio with multi-strand cores or Litz style cores, the signal transmission appears to improve when the least number of strands are used. From our understanding of reactance this makes sense: less strands means that less reactance distortion effects are generated. Further, when using multi-strand cables, small diode or rectification effects arise from imperfect contact among the strands. Again, fewer strands are better.
Signal carrying cables can comprise conductor strands other than round i.e. square, flat, rectangular, tubular etc
There are currently five types of geometry""s utilized in signal carrying cables, the coaxial, the twisted pair, the woven, the helical pair and the parallel pair.
The present invention is preferably utilized in a parallel configuration where each conductive core needs to be laid beside each other and not twisted together.
Twisting of cores increases inductive and capacitive reactance in cables. However, where specific impedance is required i.e. 75 Ohm or 110 Ohm for digital and video use, then cores may be twisted to achieve the desired impedance.
To date, there has not been a signal carrying cable design that addresses and minimizes the effects of the above mentioned reactance problems by using a specific ratio as per the present invention. There is therefore a need for this invention.

Specific cable ratio for high fidelity audio cables


According to one exemplary implementation, a dual anti-fuse structure includes a first channel in a common semiconductor fin adjacent to a first programmable gate. The dual anti-fuse structure further includes a second channel in said common semiconductor fin adjacent to a second programmable gate. A first anti-fuse is formed between the first channel and the first programmable gate. Furthermore, a second anti-fuse is formed between the second channel and the second programmable gate. The first programmable gate can be on a first sidewall of the common semiconductor fin and can comprise a first gate dielectric and a first electrode. The second programmable gate can be on a second sidewall of the common semiconductor fin and can comprise a second gate dielectric and a second electrode.

An anti-fuse can be configured in a planar arrangement with a source, a drain, and a channel situated in a semiconductor substrate. A programmable gate is situated over the channel and includes a gate electrode situated over a gate dielectric. The gate dielectric initially provides a high-resistance current path between the gate electrode and the channel of the anti-fuse. The anti-fuse can be programmed by applying a programming voltage across the gate electrode and the channel so as cause breakdown of the gate dielectric. Once programmed, the current path changes from high-resistance to low-resistance to facilitate current flow through the current path.


A cleansing composition containing the following components (A) and (B): (A) an ether carboxylate of Formula (1) R1—O—(CH2CH2O)n—CH2—COOX (1) wherein —R1 represents a linear or branched C4-C10 alkyl or alkenyl group, —n represents a number from 0.5 to 20, and —X represents a hydrogen atom or a cation selected from the group consisting of an alkali metal, an alkaline earth metal, ammonium, an alkylammonium, an alkanolammonium, and a glucammonium; and (B) an ether carboxylate of Formula (2) R2—O—(CH2CH2O)m-CH2—COOY (2) wherein —R2 represents a linear or branched C12-C22 alkyl or alkenyl group, —m represents a number from 0.5 to 20, and —Y represents a hydrogen atom or a cation, selected from the group consisting of an alkali metal, an alkaline earth metal, ammonium, an alkylammonium, an alkanolammonium, and a glucammonium.R1—O—(CH2CH2O)n—CH2—COOX  (1)R2—O—(CH2CH2O)m—CH2—COOY  (2)

Traditionally, personal cleansing was usually carried out using solid soap bars containing alkali metal salts of fatty acids (soaps) as a surfactant. Nowadays, personal cleansing is a daily activity in most countries, and cleansing compositions have to meet customer needs and preferences, such as being very mild, easy applicability, and sufficient lathering. Soap bars are not satisfactory in meeting these requirements, especially in terms of mildness.
Furthermore, in liquid formulations, soap-based systems require adding thickening agents such as highly salt-resistant polymeric components to produce viscosities preferred by consumers. This thickening approach can cause a composition to exhibit dramatic viscoelastic properties during use and impact other product performance attributes (e.g., lathering properties). Because of this, many personal cleansing compositions have been changed to surfactant formulations without soap ingredients. However, many of these formulations fail to provide a preferable rinse feel associated with the cleansed skin. As a result, such a formulation fails to provide a rinse feel similar to that provided by soap, which is desired by many customers, especially those in Asia.
The term "rinse feel" refers to the feeling of the skin when lather is rinsed from the skin following the application of a cleansing composition. The term "soap-like rinse feel" as used herein refers to a feeling similar to that provided by soap; a soap-like rinse feel is a "draggy" rinse feel generated by a friction between the hand and the skin during the rinsing process.
Several attempts have been made to provide cleansing compositions that, while exhibiting mildness, provide the soap-like rinse feel.
For example, Patent Document 1 describes a mild liquid skin cleansing composition with improved lathering and rinse feel, containing: an alkyl ethoxylated sulfate having an average degree of ethoxylation of at least 2.0; an amphoteric surfactant selected from betaine surfactants, imidazoline surfactants, aminoalkanoate surfactants, and iminodialkanoate surfactants; an N-acylamino acid surfactant or a salt thereof; a cationic cellulose ether derivative; 0.2 to 2.0 parts by weight of a C8-C20 fatty alcohol; and 0.1 to 5 parts by weight of a water-insoluble salt of a C14-C22 fatty acid. The viscosity of the composition is within the range of 5000 to 11,000 cps.
Patent Document 2 describes a mild personal cleansing composition containing: (a) 3 to 10 parts by weight of an alkyl ethoxylated sulfate having an average degree of ethoxylation of at least 2.0; (b) 3 to 10 parts by weight of an amphoteric surfactant selected from betaine surfactants, imidazoline surfactants, aminoalkanoate surfactants, and iminodialkanoate surfactants; (c) 0.1 to 3 parts by weight of an N-acylamino acid surfactant or a salt thereof; (d) 0.01 to 0.5 parts by weight of a cationic cellulose ether derivative; (e) 50 to 94 parts by weight of water; and (f) 0.2 to 2.0 parts by weight of a C8-C20 fatty alcohol. Also a method of producing a personal cleansing composition is described. It is stated that the composition is mild and lathers well with an improved rinse feel.
Patent Document 3 describes a cleansing composition providing a soap-like rinse feel. The composition contains a lathering surfactant system, specific polymers, and oil ingredients.
Patent Document 4 describes a rinse-off liquid personal cleansing composition containing surfactants and water, wherein the composition contains less than 8% by weight of a first surfactant selected from crystallizing anionic surfactants and contains greater than 3% by weight of a second surfactant selected from non-crystallizing anionic surfactants, amphoteric surfactants, nonionic surfactants, and zwitterionic surfactants.
Patent Document 5 describes a liquid personal cleansing composition containing water, about 1% to about 60% by weight of a water-soluble surfactant, and a water-insoluble oil selected from highly branched poly-α-olefins having a number average molecular weight of about 1000 to about 25,000.
Also, Patent Document 6 describes a liquid personal cleansing composition containing surfactants, water, and water-insoluble oils.
Further, Patent Document 7 describes a liquid personal cleansing composition containing water, surfactants, and 0.5% by weight or greater of water-insoluble oils, wherein the water-insoluble oils provide a mean change in friction meter reading for the composition of 2 or greater as measured by a friction meter technical test method.
As described above, the personal cleansing compositions described in Patent Documents 1 to 7 provide an improved rinse feel. It is stated that these compositions provide an excellent rinse feel, which is a "draggy" and "soap-like" rinse feel, and also are mild to the skin. However, the above compositions cannot be completely considered to provide a soap-like rinse feel, and also they have a different texture from that of soap.


The current invention comprises an approach to solving the clinical problem of restenosis, which involves the administration of combinations of drugs to patients undergoing PTCA or stent implantation. In one embodiment of the invention, an antiproliferative agent such as rapamycin, vincristine or taxol is administered in combination with the antiinflammatory agent, dexamethasone, to patients systemically, either subcutaneously or intravenously. In another embodiment of the invention, the antiproliferative and antiinflammatory agents are bound in a single formulation to the surface of a stent by means of incorporation within either a biodegradable or biostable polymeric coating. Alternatively, such drug combinations could be incorporated into a stent constructed with a grooved reservoir.

Atherosclerotic lesions, which limit or obstruct coronary blood flow, are the major cause of ischemic heart disease related mortality, resulting in 500,000-600,000 deaths annually. Percutaneous transluminal coronary angioplasty (PTCA) to open the obstructed artery was performed in over 550,000 patients in the U.S. and 945,000+ patients worldwide in 1996 (Lemaitre et al., 1996). A major limitation of this technique is the problem of post-PTCA closure of the vessel, both immediately after PTCA (acute occlusion) and in the long term (restenosis): 30% of patients with subtotal lesions and 50% of patients with chronic total lesions will go on to restenosis after angioplasty. Additionally, restenosis is a significant problem in patients undergoing saphenous vein bypass graft. The mechanism of acute occlusion appears to involve several factors and may result from vascular recoil with resultant closure of the artery and/or deposition of blood platelets along the damaged length of the newly opened blood vessel followed by formation of a fibrin/red blood cell thrombus.
Restenosis after angioplasty is a more gradual process and involves initial formation of a subcritical thrombosis with release from adherent platelets of cell derived growth factors with subsequent proliferation of intimal smooth muscle cells and local infiltration of inflammatory cells contributing to vascular hyperplasia. It is important to note that multiple processes, among those including thrombosis, cell proliferation, cell migration and inflammation each seem to contribute to the restenotic process.
In the U.S., a 30-50% restenosis rate translates to 120,000-200,000 U.S. patients at risk from restenosis. If only 80% of such patients elect repeat angioplasty (with the remaining 20% electing coronary artery bypass graft) is added to the cost of coronary artery bypass graft for the remaining 20%, the total cost for restenosis easily reaches into billions of dollars. Thus, successful prevention of restenosis could result not only in significant therapeutic benefit but also in significant health care savings.
While the exact mechanism for restenosis is still uncertain, the general aspects of the restenosis process have been identified:                1) In the normal arterial wall, smooth muscle cells (SMC) proliferate at a low rate (<0.1%/day). SMC in vessel wall exists in a 'contractile' phenotype characterized by 80-90% of the cell cytoplasmic volume occupied with the contractile apparatus. Endoplasmic reticulum, Golgi, and free ribosomes are few and located in the perinuclear region. Extracellular matrix surrounds SMC and is rich in heparin-like glycosylaminoglycans which are believed to be responsible for maintaining SMC in the contractile phenotypic state (Campbell and Campbell, 1985).        2) Upon pressure expansion of an intracoronary balloon catheter during angioplasty, smooth muscle cells within the arterial wall become injured, initiating a thrombotic and inflammatory response. Cell derived growth factors such as platelet derived growth factor (PDGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), thrombin, etc., released from platelets (i.e., PDGF) adhering to the damaged arterial luminal surface, invading macrophages and/or leukocytes, or directly from SMC (i.e., bFGF) provoke a proliferation and migratory response in medial SMC. These cells undergo a phenotypic change from the contractile phenotype to a 'synthetic' phenotype characterized by only few contractile filament bundles but extensive rough endoplasmic reticulum, Golgi and free ribosomes. Proliferation/migration usually begins within 1-2 days post-injury and peaks at 2 days in the media, declining thereafter (Campbell and Campbell, 1987; Clowes and Schwartz, 1985).        3) Daughter synthetic cells migrate to the intimal layer of arterial smooth muscle and continue to proliferate and begin to secrete significant amounts of extracellular matrix proteins. Proliferation, migration and inflammation continue until the damaged luminal endothelial layer regenerates at which time proliferation slows within the intima, usually within 7-14 days postinjury. The further increase in intimal thickening that occurs over the next 3-6 months is due primarily to an increase in extracellular matrix rather than cell number. Thus, SMC migration and proliferation is an acute response to vessel injury while intimal hyperplasia is a more chronic response. (Liu et al., 1989).        4) Simultaneous with local proliferation and migration, inflammatory cells adhere to the site of vascular injury. Within 3-7 days post injury, luminal adherent cells decline due to migration of inflammatory to the deeper layers of the vessel wall. In animal models employing either balloon injury or stent implantation, inflammatory cells may persist at the site of vascular injury for at least 30 days (Tanaka et al., 1993; Edelman et al., 1998). Inflammatory cells therefore are present and may contribute to both the acute and chronic phases of restenosis.
Numerous agents have been examined for presumed antiproliferative actions in restenosis and have shown some activity in experimental animal models. Some of the agents which have been shown to successfully reduce the extent of intimal hyperplasia in animal models include: heparin and heparin fragments (Clowes, A. W. and Karnovsky M., Nature, 265: 25-26, 1977; Guyton, J. R. et al., Circ. Res., 46: 625-634, 1980; Clowes, A. W. and Clowes, M. M., Lab. Invest. 52: 611-616, 1985; Clowes, A. W. and Clowes, M. M., Circ. Res. 58: 839-845, 1986; Majesky et al., Circ Res. 61: 296-300, 1987; Snow et al., Am. J. Pathol. 137: 313-330, 1990; Okada, T. et al., Neurosurgery 25: 92-98, 1989), colchicine (Currier, J. W. et al., Circulation 80: II-66, 1989, taxol (Sollott, S. J. et al., J. Clin. Invest. 95: 1869-1876, 1995), angiotensin converting enzyme (ACE) inhibitors (Powell, J. S. et al., Science, 245: 186-188, 1989), angiopeptin (Lundergan, C. F. et al., Am. J. Cardiol. 17(Suppl. B): 132B-136B, 1991), cyclosporin A (Jonasson, L. et. al., Proc. Natl., Acad. Sci., 85: 2303, 1988), goat-anti-rabbit PDGF antibody (Ferns, G. A. A., et al., Science 253: 1129-1132, 1991), terbinafine (Nemecek, G. M. et al., J. Pharmacol. Exp. Thera. 248: 1167-1174, 1989), trapidil (Liu, M. W. et al., Circulation 81: 1089-1093, 1990), tranilast (Fukuyama, J. et al., Eur. J. Pharmacol. 318: 327-332, 1996), interferon-gamma (Hansson, G. K. and Holm, J., Circulation 84: 1266-1272, 1991), rapamycin (Marx, S. O. et al., Circ. Res. 76: 412-417, 1995), steroids (Colburn, M. D. et al., J. Vasc. Surg. 15: 510-518, 1992), see also Berk, B. C. et al., J. Am. Coll. Cardiol. 17: 111B-117B 1991, ionizing radiation (Weinberger, J. et al., Int. J. Rad. Onc. Biol. Phys. 36: 767-775, 1996), fusion toxins (Farb, A. et al., Circ. Res. 80: 542-550, 1997) antisense oligonucleotides (Simons, M. et al., Nature 359: 67-70, 1992) and gene vectors (Chang, M. W. et al., J. Clin. Invest. 96: 2260-2268, 1995). Antiproliferative action on SMC in vitro has been demonstrated for many of these agents, including heparin and heparin conjugates, taxol, tranilast, colchicine, ACE inhibitors, fusion toxins, antisense oligonucleotides, rapamycin and ionizing radiation. Thus, agents with diverse mechanisms of SMC inhibition may have therapeutic utility in reducing intimal hyperplasia.
However, unlike animal models, attempts in human angioplasty patients to prevent restenosis by systemic pharmacologic means have thus far been unsuccessful. Neither aspirin-dipyridamole, ticlopidine, anticoagulant therapy (acute heparin, chronic warfarin, hirudin or hirulog), thromboxane receptor antagonism nor steroids have been effective in preventing restenosis, although platelet inhibitors have been effective in preventing acute reocclusion after angioplasty (Mak and Topol, 1997; Lang et al., 1991; Popma et al., 1991). Additionally, the 7E3 humanized monoclonal antibody fragment to the platelet GP IIb/IIIa receptor is still under study but has not shown promising results for the reduction in restenosis following angioplasty and stenting. Other agents, which have also been unsuccessful in the prevention of restenosis, include the calcium channel antagonists, prostacyclin mimetics, angiotensin converting enzyme inhibitors, serotonin receptor antagonists, and antiproliferative agents. These agents must be given systemically, however, and attainment of a therapeutically effective dose may not be possible; antiproliferative (or anti-restenosis) concentrations may exceed the known toxic concentrations of these agents so that levels sufficient to produce smooth muscle inhibition may not be reached (Mak and Topol, 1997; Lang et al., 1991; Popma et al., 1991).
Additional clinical trials in which the effectiveness for preventing restenosis of dietary fish oil supplements or cholesterol lowering agents has been examined have shown either conflicting or negative results so that no pharmacological agents are as yet clinically available to prevent post-angioplasty restenosis (Mak and Topol, 1997; Franklin and Faxon, 1993; Serruys, P. W. et al., 1993). Recent 920 observations suggest that the antilipid/antioxident agent, probucol may be useful in preventing restenosis but this work requires confirmation (Tardif et al., 1997; Yokoi, et al., 1997). Probucol is presently not approved for use in the United States and a 30-day pretreatment period would preclude its use in emergency angioplasty. Additionally, application of ionizing radiation has shown significant promise in reducing or preventing restenosis after angioplasty in patients with stents (Teirstein et al., 1997). Currently, however, the most effective treatments for restenosis are repeat angioplasty, atherectomy or coronary artery bypass grafting, because no therapeutic agents currently have US Federal Regulatory Agency (FDA) approval for use for the prevention of post-angioplasty restenosis.
Unlike systemic pharmacologic therapy, stents have proven useful in partially preventing restenosis. Stents, are balloon-expandable slotted metal tubes (usually, but not limited to, stainless steel), which, when expanded within the lumen of an angioplastied coronary artery, provide structural support to the arterial wall. This support is helpful in maintaining vessel lumen patency. In two randomized clinical trials, stents increased angiographic success after PTCA, by increasing minimal lumen diameter and reducing, (but not eliminating,) the incidence of restenosis at 6 months (Serruys et al., 1994; Fischman et al., 1994).
Additionally, in a preliminary trial, heparin coated stents appear to possess the same benefit of reduction in stenosis diameter at follow-up as was observed with non-heparin coated stents. Heparin coating also appears to have the added benefit of producing a reduction in sub-acute thrombosis after stent implantation (Serruys et al., 1996). Thus, 1) sustained mechanical expansion of a stenosed coronary artery with a stent has been shown to provide some measure of restenosis prevention, and 2) coating of stents with heparin has demonstrated both the feasibility and the clinical usefulness of delivering drugs locally, at the site of injured tissue.
Post-angioplasty restenosis is a multifactoral process that involves numerous interactive mechanisms. This means that effective prevention of restenosis may not be feasible with agents possessing a single mechanism of action; positive therapeutic results may be best achieved through application of several agents with differing therapeutic targets. Thus, potential therapeutic benefit could be found with the co-delivery of agents with different mechanisms of action targeting different components of the restenosis process.

Drug combination useful for prevention of restenosis


In a wireless communication apparatus in a time division duplex system, a transmission signal generation unit generates a transmission signal. A power amplifying device amplifies the generated transmission signal. A control signal generation device generates a drain voltage control signal for control of the drain voltage of the power amplifying device, and a gate voltage control signal for control of the gate voltage of the power amplifying device. The switch unit switches off the drain power supply of the power amplifying device during reception in the time division duplex system according to the drain voltage control signal. In addition, the power amplifying device sets a higher gate voltage during reception in the time division duplex system higher than during transmission according to the gate voltage control signal.

1. Field of the Invention
The present invention relates to the technology of controlling a power amplifier, and more specifically to a power amplifier used in a wireless transmission/reception device in a time division duplex system.
2. Description of the Related Art
In the time division duplex system (hereinafter referred to as TDD for short), a communication path is divided by a time axis, a transmission/reception switch is quickly made, and a frequency band is shared between a transmitter and a receiver. As shown in FIGS. 1A and 1B, a switch and a circulator are provided immediately below an antenna so that communications can be performed by switching between transmission and reception.
In the TDD system, a frequency band is shared between transmission and reception. Therefore, it is necessary that isolation is completely secured between a transmission unit and a reception unit. When the isolation is not sufficient, there occur problems such as a leak of a transmission signal to the reception unit, saturating a low noise amplifier, etc. For example, when a transmission/reception changeover switch is provided, the transmission/reception switch time is shorter at a higher transmission rate. Then, with a shorter transmission/reception switch time, it becomes more difficult to secure the isolation.
To secure the isolation, it is desired that the power amplifier of the transmission unit is turned on and the low noise amplifier of the reception unit is turned off during transmission, and that the power amplifier of the transmission unit is turned off and the low noise amplifier of the reception unit is turned on during reception. It is necessary from the viewpoint of improving power efficiency.
Assume a power amplifier using a field effect transistor. In this case, since a power current passing through a drain is large in the power amplifier, the current value is not immediately set to zero due to transient response although the voltage to be applied to the drain is switched off. Therefore, the residual signal is leaked to the reception side, thereby possible degrading the reception performance.
As the technology for controlling the on/off state of the power amplifier to solve the above-mentioned problems, for example, Japanese Published Patent Application No. H9-74321 discloses the technology of providing an emitter unit of a high frequency amplification transistor with a switching element together with an emitter resistor and setting an active state during reception and passive state during transmission, thereby turning on/off a high frequency amplification transistor.
As another technique for controlling the on/off state of the power amplifier, for example, Japanese Published Patent Application No. H4-373317 discloses the technology of providing a transmitting power amplifier and a receiving power amplifier to turn off the transmitting power amplifier by the control voltage during reception and turn on the receiving power amplifier. Then, the receiving power amplifier is turned off and the transmitting power amplifier is turned on by the control voltage during transmission.
The methods disclosed by the above-mentioned Japanese Published Patent Application No. H9-74321 and Japanese Published Patent Application No. H4-373317 switch on and off the transmitting power amplifier to suppress a leak of the transmission signal to the reception unit in the TDD system. However, as described above, since the current passing through the drain of the power amplifier is large, it is not easy to quickly switch on/off the power amplifier by the switch circuit.

Wireless communication apparatus, power amplifier control method, and power amplifier control apparatus


The present invention provides a control valve with an improved closing function that functions over a long period of time and the flow rate control can be carried out over a wide range.. A valve body (1) is provided inside thereof with a partition (4) separating an inlet passage (2) and an outlet passage (3). The partition (4) is provided with an opening portion (5) communicating the inlet passage (2) and the outlet passage (3).. A shutoff valve (10) is disposed opposite the opening portion (5). The diameter of the opening portion (5) is increased and curves toward the side of the shutoff valve (10).. A control plug (12) is arranged on and projected from the lower end of the shutoff valve (10); said control plug being located on the large diameter side of the opening portion (5), is coaxial with the opening portion (5), and has a flange portion (12a) defining an orifice (14) between the inner surface of the opening portion (5) and the flange portion. The shutoff valve is movable up and down and allows the lower end (11) thereof to abut against a valve seat portion (15) formed on the periphery of the opening portion (5).

A control valve in the prior art, for example, as shown in FIG. 13, has the problem that, when controlling at a low opening range, i.e., at the lower limit of the valve rangeability, if the flow rate of a fluid is controlled, a valve plug and a valve seat are locally eroded by the cavitation of the fluid occurring owing to a variation of a pressure condition in the front and rear of the valve, and the amount of fluid leakage on the valve closing is increased by the above cavitation, and thus precise control is difficult, consequently, the control valve fails to operate.
Accordingly, various proposals aimed at preventing fluid leakage owing to the occurrence of the cavitation when the valve is closed have been made. Among the above proposals, an example is disclosed in Japanese Unexamined Patent Publication No. 59-34073. The control valve disclosed in the above publication is designed such that a valve plug having two large and small barrels is provided so as to move up and down in relation to an inner hole comprising a small diameter portion adjacent to a valve seat and a vertical wall portion larger than the small diameter portion, and an increased diameter portion, the hole wall of which is formed in a horn-shape spreading downward so that corrosion of the valve plug and the valve seat owing to the occurrence of the cavitation, and fluid leakage on the valve closing are prevented; also, the flow rate control is carried out in the minimum opening portion defined by the circumferential surface of the large barrel portion or the resting portion and the inner hole, according to the movement of the valve plug.
Nevertheless, in such a conventional control valve, since it is necessary to rub the resting portion and the valve seat portion by lapping so that the interface of the above portions is made conformable, there are problems in that machining is troublesome, high precision is required, and the interface is worn because of repeated opening and closing valve operations, and thus the valve fails to close.
Also, although the flow characteristics of the control valve are obtained by changing the minimum opening portion area defined by the inner hole and the valve plug, the flow characteristics corresponding to its design is not easily obtained because the valve plug is cylindrical and the configuration is liable to be subjected to resistance due to the viscosity of the fluid, and thus it is difficult to increase the range ability.
Furthermore, the conventional diaphragm valve generally has a construction as shown in FIG. 14 of the accompanying drawings, there is no dead space in the interior of the valve when the fluid is flowing and the reliability of its fluid-stopping ability is high, and thus many diaphragm valves are used in super pure water pipe lines in the semiconductor industry to prevent the growth of bacteria, in the bio-industry in the field of medicine and cosmetics, and in all kinds of chemical pipe lines. Further, the prior arts concerning the diaphragm valves and the diaphragms themselves used in the above applications are disclosed in Japanese Examined Utility Model Publication No. 2-3026 and 63-37578, etc. Also, as a substitute for the diaphragm valve, "fluororesin bellows for bellows-seal valve" is disclosed in Japanese Examined Utility Model Publication No. 42-21903. These prior arts use superior techniques in that the growth of bacteria can be prevented as stated above and the fluid stopping ability thereof is very reliable.
Nevertheless, with the constitution of the prior art, since no consideration is given to designing the inherent flow characteristics of the valve, a similar percentage of characteristics or linear flow characteristics essential to general automatic control valves cannot be obtained according to the design. Thus, if one intends to carry out automatic control, such as PID control, the controlling-ability is very poor, and in particular, the conventional control valves are not suitable for special process lines requiring precision, and even in general process lines, hunting occurs and thus the control valves often fail to operate and control. Further, it is natural for the controllable range of the flow rate to be limited since the rangeability is very small. Also, if the control valve is used in a low opening range, a rapid pressure drop occurs under certain conditions and cavitation is brought about. Thus, the possibility of the valve plug portion and the valve seat portion being damaged is high, thereby reducing the reliability of the fluid stop ability thereof.


Polyvinyl chloride reactor wall scale is reduced by conducting the polymerization in the presence of a phenothiazine dimer or higher oligomer made by reacting an aldehyde such as acetaldehyde or benzaldehyde with phenothiazine, or by reacting 2-acetylphenothiazine with formaldehyde.

1. Field of Invention
U.S. Pat. Nos. 4,853,446 and 4,855,424 disclose and claim novel compounds and compositions which have been found to inhibit the build-up of scale on the walls of vinyl chloride polymerization reactors. Such reactor scale interferes with heat transfer, and consumes valuable monomer which is lost to the final products, and results in the increase in waste product that must be disposed of safely.
The above listed patents disclose the use of the additive of the invention in various polymerization reactions for making polyvinyl chloride including emulsion polymerization, bulk or mass polymerization, suspension polymerization and microsuspension polymerization.
Copending application Ser. No. 07/424,435 filed on even date herewith, discloses and claims the use of the compounds and compositions disclosed in the foregoing patents in a microsuspension process wherein the polymerization is conducted in a tubular reaction zone without agitation. The disclosure of this copending application is incorporated herein by reference. The latter microsuspension process is disclosed and claimed in U.S. Pat. Nos. 2,981,722; 4,377,672 and 4,528,327, the disclosures of which are incorporated by reference. In this process, the tubular reactor is preferentially vertically elongated and preferably has a substantially circular cross-section.
The purpose of this invention is to provide improved polyvinyl chloride polymerization processes that utilize certain phenothiazine derivatives to reduce reactor wall fouling or scale deposits, as well as flocculated material during polymerization of vinyl chloride and comonomers.
2. Prior Art
U.S. Pat. No. 2,415,252 describes the preparation of phenothiazine derivatives by reacting phenothiazine with formaldehyde and an alcohol under conditions that produce a modified phenothiazine that has attached thereto a methylene group and an alkoxy group. The compounds and their solutions in oil are said to be useful for pharmaceutical, veterinary and pest-control purposes.
U.S. Pat. No. 2,528,092 describes the reaction of phenothiazine with formaldehyde and N-dimethylaniline. The resulting compound is useful as an antioxidant for mineral oil lubricants.
U.S. Pat. No. 4,465,881 describes N,N'-dimers of phenothiazine or a substituted phenothiazine. The compounds result from the linkage of two phenuchiazine molecules through their N groups. These dimers are prepared by heating phenothiazine in the presence of an organic peroxide. These dimers are disclosed to be useful to stabilize vinyl aromatic compounds such as styrene and substituted styrenes against undesired polymerization.
U.S. Pat. No. 4,529,500 discloses the use of the N,N'-dimer of phenothiazine or a substituted phenothiazine to protect hydrocarbon processing equipment against fouling during the processing of hydrocarbons at elevated temperatures.
An article published in the U.S.S.R. by Romanovich and co-authors and reported in Chemical Abstracts as 98:144251d, describes the reaction of phenothiazine and formaldehyde under conditions that favor the production of hardened products, wherein reaction appears to take place at the nitrogen group of the phenothiazine, ultimately resulting in the formation of cross-linked products of relatively high molecular weight.
In U.S. Pat. No 4,229,510, a polymer material is formed from a substituted phenothiazine wherein the nitrogen group is substituted with an alkyl group. It appears that reaction with formaldehyde occurs between the phenyl groups and formaldehyde. The resulting product has the nitrogen group blocked with the alkyl group of the starting material. The resulting products are reported to have photoconductive properties.
U.S. Pat. No. 4,565,834 describes compounds that have the formula of a dimer or polymer of phenothiazine. The patentees' compositions are useful as stabilizer-containing reactive components for the production of polyurethane foams which have little or no tendency toward core decolorization.

Use of phenothiazine derivatives to inhibit scale build up during polymerization of vinyl chloride


An optical component or optical low-pass filter has two or more regions demarcated by differences in refractive indexes, in which a region having a refractive index different from the refractive index of the continuous region with the largest volume among the two or more regions is formed in the interior of a transparent material. This optical component or optical low-pass filter has regions with different refractive indexes formed in the interior by pulsed laser irradiation or focused irradiation of the transparent material.

Priority is claimed on Japanese Patent Application No. 2004-351632, filed Dec. 3, 2004, the content of which is incorporated herein by reference.
1. Field of the Invention
This invention relates to an optical component manufactured using pulsed laser beam, and in particular pulsed laser beam the time duration of which is 10−12 second or less, such as femtosecond (10−15 second) pulses, and in particular relates to an optical low-pass filter suitable for solid-state image capture elements such as are used in video cameras, digital still cameras, fiberscopes and similar, as well as a manufacturing method for same. Such components are also suitable for use as optical low-pass filters in liquid crystal, plasma, EL, SED and other displays, and other dot-matrix display devices.
2. Description of Related Art
The spread of digital video cameras and digital still cameras in recent years has been accompanied by progress toward greater compactness of optical systems and higher pixel densities.
The digital video cameras and digital still cameras have solid-state image capture elements with pixels arranged in a discontinuous but regular array. Through spatial optical sampling of the object image, an image capture output is obtained corresponding to each of the pixels of the object image.
In a solid-state image capture element which thus optically samples the object image, the fineness of patterns which can be handled is determined in relation to the sampling frequency; if spatial frequency components at frequencies higher than the Nyquist frequency (hereafter called the "cutoff frequency"), which is one-half the sampling frequency, are included in the object image, then spurious signals due to aliasing artifacts may occur, so that, for example, in a color video camera, colors unrelated to the colors of the object may appear as such spurious signals in the reproduced images. Hence in devices having such solid-state image capture elements, optical low-pass filters which limit the object high spatial frequency components are positioned in the image capture optical system, to prevent the occurrence of spurious signals due to aliasing artifacts.
As such optical low-pass filters, conventional filters are widely known which utilize the birefringence of quartz to maintain contrast as high as possible with respect to lower spatial frequency components than the cutoff frequency.
Also in the prior art, focusing on the fact that the autocorrelation function of the pupil function of a focusing optical system provides the transfer function for the system (the absolute value of which is hereafter abbreviated "MTF"), a phase-type optical low-pass filter has been proposed in which the pupil function is intentionally provided with aberration to obtain the target optical characteristics. That is, the MTF represents the contrast with the spatial frequency, and so by inserting into the optical system an optical component which provides an MTF characteristic such that the contrast in the high spatial frequency region, above the cutoff frequency determined by the pixel aperture width and pitch, is made low, spurious-signal images due to aliasing are made less prominent.
As such a phase-type optical low-pass filter has, for example, a component which is a transparent substrate of glass, resin or similar, with a stripe-shape periodic structure formed on the surface thereof and is inserted into an optical system. Differences between the optical distances of transmitted light, that is, phase differences, are imparted by the stripe-shape periodic structure, changing the phase terms of the pupil function, to realize optical low-pass filter characteristics.
Various methods have been disclosed relating to the method of fabrication of such a phase-type optical low-pass filter. For example, a lithography method which uses semiconductor fabrication techniques is known. Here, a photosensitive resin film applied to the glass or other substrate is subjected to mask exposure using a photomask or to interference exposure, followed by development, to fabricate a photosensitive film pattern on the glass. Then, by performing dry etching treatment from above, a pattern is simultaneously etched in the glass exposed at the surface and in the photosensitive film; when at last the photosensitive film is consumed, depressions have been formed by etching in the glass surface, and the overall result is formation of a diffraction grating consisting of the glass substrate.
In addition, a method in which a pattern is created in metal or a single crystal by the above means, and this is used as a die in hot pressing and injection molding to transfer a pattern, as well as a method in which a photosetting resin is poured into such a die, and the resin is hardened into the shape of the die through irradiation with ultraviolet rays or similar, are also known (see Japanese Unexamined Patent Application, First Publication No. 6-308430).
In Japanese Unexamined Patent Application, First Publication Nos. 6-242404 and 7-5395, a method is disclosed in which a diamond wheel is used in grinding to cut a stripe structure with regular protrusions and depressions on a substrate surface.
In Japanese Unexamined Patent Application, First Publication No. 61-149923, a method is disclosed in which an ion-exchange method or similar is employed to form portions on a glass surface with different refractive indexes, to fabricate a phase-type diffraction grating.
On the other hand, advances in laser pulse compression technology in recent years have been accompanied by numerous reports on the fabrication of transparent materials using ultra-short-pulse laser light. In particular, the high peak power of laser light with pulse duration of femtosecond order are known to have made possible three-dimensional fabrication of the interior of transparent materials, utilizing multi-photon absorption processes. In Japanese Unexamined Patent Application, First Publication No. 9-311237, a method is disclosed in which laser light irradiation is used to form a high-refractive index region within glass, to form a three-dimensional optical waveguide. Further, Japanese Unexamined Patent Application, First Publication No. 2000-56112 discloses a method of using laser light irradiation to induce a permanent three-dimensional distribution of the refractive index within glass material, to create an optical diffraction element.
With respect to irradiation methods for femtosecond laser light, a fabrication method is known in which the pulse beam is focused by a lens and the focal point is scanned (in addition to the above, see Published Japanese Translation No. 2003-506731 of PCT International Publication), and in Japanese Unexamined Patent Application, First Publication No. 2004-196585, a method is disclosed in which a refractive index-modified area, with a two-dimensional or three-dimensional shape, is formed at once within glass or some other transparent material, using a laser beam without a scanning mechanism.
An optical low-pass filter which employs the birefringence of quartz incurs the expensive raw material costs of the quartz, and in particular requires a plurality of sheets of quartz and becomes thick when contemplating use in a color video camera using a solid-state image capture element, so that there are limits placed on the compactness of the optical system. Moreover, problems of precise optical axis alignment, and of strain when bonding sheets together, as well as numerous other problems related to manufacture make such components unsuitable for mass production.
On the other hand, conventional optical low-pass filters employing phase-type diffraction gratings, obtained by fabrication the surface of a material, have the following problems from the standpoint of device manufacture.
For example, when using lithography, there are numerous processes as explained above, and the time required leads to increased fabrication costs. On the other hand, when an attempt is made to for example fabricate a rectangular-shape grating with large step height differences, in consideration of the ease of fabrication, it is not easy to machine grooves which are deep in the vertical direction. Further, it may be necessary to select optimal environment conditions for dry etching depending on the material, and in other respects also control is complicating, and there is little degree of freedom in choice of materials. In addition, due to the nature of the fabrication method, fabrication of the surface is limited to two dimensions, so that there is little degree of freedom in the design of the structure.
On the other hand, when using a mold fabricated using lithography, mass production is improved compared with cases in which lithography is used to directly machine a substrate, and so there is the advantage that costs can be kept low. However, limitations are imposed on the selection of materials. That is, in the case of a hot-pressed replica, the material for fabrication is limited to glass and resin. In the case of the photopolymer method described in Japanese Unexamined Patent Application, First Publication No. 6-308430 also, the material is limited to a photosensitive resin. Further, in the case of a hot-pressed replica, when choosing the mold and material for fabrication, the durability of the mold with respect to the softening temperature of the glass is an issue; and conversely, the material should be preferably selected with this born in mind.
When cutting using a diamond wheel, mass production properties are poor compared with molding of glass or resin using a mold, and there are problems with fabrication multiple-angled or curving filter patterns. Accordingly, there is little degree of freedom in choosing shapes at the design stage, and shape precision is poor. Moreover, the mechanical strength of the material becomes an issue, so that there is little degree of freedom in choice of material as well.
Methods in which ion exchange techniques or similar are used to form portions on a glass surface the refractive index of which differs are in essence material surface fabrication methods, and so there is little degree of freedom of pattern design. In the case of ion exchange methods, a metal mask or similar must be formed by the above-described photolithography in order to obtain the desired pattern. This is performed by immersion in a fused-salt reactor, and the processes involved are complex.
On the other hand, with respect to internal fabrication using the above ultra-short pulse laser light, the above-mentioned Japanese Unexamined Patent Application, First Publication No. 2004-196585 describes a number of examples of optical components for optical communication, fabricated by forming regions in which the refractive index changes according to three-dimensional shapes. Further, the above-mentioned Japanese Unexamined Patent Application, First Publication No. 2000-56112 describes a method of fabrication of a three-dimensional volume-type diffraction grating, with applications as a Bragg diffraction grating employing regions in which the refractive index changes in layers. However, in none of these disclosures are applications to optical components which control the phase of light transmitted therethrough, and in particular to optical low-pass filters, discussed.

Optical component and method of manufacture of optical component


A packaging container with a clamping base and an attachable protective cap serves for a unilateral, clamping or holding of a tool, an instrument, or another longitudinal object, where the clamping base comprises a clamping holder with a plurality of springy clamping jaws fastened on one side which define a nearly centric, central clamping reception, in which clamping reception the tool is inserted and held clampingly.

Such packaging container with a clamping base has become known as such that a cap can be slid on a base. By this the cap covers the object to be protected, for example a tool, an instrument, or any other object, which object is received by the base of the packaging container.
The known clamping base is developed as such that a clamping reception is formed in the area of the base by ribs arranged at the circumference uniformly distributed, which ribs are fixed at the internal surfaces of the base. At their corresponding ends the ribs project radially inwardly and as such they form a clamping reception. Since the ribs are made of a flexible material this results in a flexible clamping reception in case that the object to be held is inserted in the clamping reception which results in a partial deformation of these flexible ribs.
A disadvantage of this known clamping reception is that when the object to be held is inserted, the clamping force is as great as the clamping force in accordance with holding the object in the clamping reception. Hence follows that there is no change of the clamping force, which is connected with the following disadvantages.
A first disadvantage is that it is difficult to equip such packaging container, because the object to be held must be inserted in the clamping reception by overcoming the clamping force (with partial considerable force to be applied by the hand) of said clamping reception.
If the object is a sharp-edged tool or the like this will result in injuries of the hand due to the insertion force or holding force necessary to operate the tool.
A further disadvantage is that the clamping force can in no way be increased if the object is held in the clamping reception. The cap covering the base has no function when this object is held.
Therefore, it is the problem of the invention to further develop a packaging container of the kind mentioned above as such that the object to be held and clamped can be inserted in the clamping reception relatively easy and is held there with a great holding force.

Abstract: In order to achieve that the insertion force to be applied is low when the packaging container is equipped, however, a high clamping force is given with the protective cap attached. The protective cap abuts against the outside circumference of the clamping jaws when it is attached to the clamping base and prestresses said clamping jaws in direction of the clamping reception.


A transmission circuit includes a first path that connects a first terminal for inputting or outputting signals, and one of a pair of second terminals for outputting or inputting the signals; a second path that connects the first terminal and another one of the pair of second terminals; a first circuit including a first capacitor that is serially inserted in the first path, which is configured to perform single-differential conversion on signals transmitted through the first path, to perform impedance matching, and to supply a bias voltage; a second circuit including a first inductor that is serially inserted in the second path, which is configured to perform single-differential conversion on signals transmitted through the second path, to perform impedance matching, and to supply a bias voltage; and a switch that is connected between the two terminals of the pair of second terminals.

Conventionally, there is an antenna duplexer which is used by switching a single antenna by transmission signals and reception signals having different frequencies. This antenna duplexer includes a high frequency switch circuit that supplies transmission signals to the antenna, and a band limit filter that outputs reception signals output from the antenna to a predetermined reception circuit. In the band limit filter, frequency characteristics are selected such that the frequency band of the transmission signal is suppressed, and the reflected wave generated at the input terminal is maintained at a predetermined phase such that the impedance becomes high at the frequency band of the transmission signal.
Furthermore, the antenna duplexer switches the contact point of the switch circuit, and switches the transistor to an ON state at the time of transmission or switches the transistor to an ON state at the time of reception, and selectively connects the single antenna to the transmitting circuit and the receiving circuit (see, for example, Patent Document 1).    Patent Document 1: Japanese Laid-Open Patent Publication No. H06-291696
Incidentally, a conventional antenna duplexer includes a switch in the transmission path of the transmission signal or the reception signal, and therefore a loss occurs when the transmission signal or the reception signal is transmitted to the switch.

Transmission circuit and signal transmission and reception circuit


Provided is a high-speed high-stand device for taking up fabric comprising two side boxes each including a projection formed on its side proximate top; a take-up shaft provided across intermediate portions of the side boxes, the take-up shaft being adapted to wind fabric therearound; and a friction mechanism including two arms each having the other end pivotably connected to the projection, and a friction rod fixedly interconnected one ends of the arms, the friction rod being provided above the take-up shaft to contact the fabric wound therearound. In a fabric take-up process, an angle from an initial position of the arms to an operating position thereof is limited as a diameter of the fabric is increasing, and a pressing force exerted by the friction rod on the fabric being wound around the take-up shaft is the same for obtaining a uniform tautness of the wound fabric.

In a knitting machine, a take-up device is typically employed to wind fabric in rolls. One type of take-up device can wind fabric in rolls having a diameter of about 20 inches. It is not widely employed due to its small capacity. The other type of take-up device, as the widely employed one due to it high capacity, can wind fabric rolls having a diameter of about 46 inches (i.e., fabric weight more than 100 kg). However, for the latter one centrifugal force increases as fabric is winding on a take-up shaft. Further, fabric is pliable in nature. Thus, fabric tends to throw away in the winding process.
U.S. Pat. No. 6,637,241 entitled "Fabric Take-Up Apparatus" aims at solving the above problem. However, the patent still has a drawback as detailed below by referring to FIGS. 1A and 1B. The fabric take-up apparatus 100 comprises two sets of friction mechanisms 110. Each friction mechanism 110 has two operating arms 112 each having axles 112a and 112b both at the same side of and above an axis of the shaft 120 for taking up fabric. A virtual line from one operating arm 112 to the other operating arm 112 is about perpendicular to a virtual line extended upward from the axis of the shaft 120 in the fabric winding process. Initially, force applied on the fabric 10 is provided by weight of the edge of the friction rods 111. Further, the extent of the perpendicularity is almost 90 degrees as fabric 10 continues to wind around the shaft 120 (i.e., diameter of fabric 10 increases). At this time, force applied on the fabric 10 is provided by weight of the whole friction rods 111. Thus, force applied on the fabric 10 is not constant in the fabric winding process. In fact, force applied on the fabric 10 is increasing in the process. For solving this problem, a balancing weight mechanism 130 is provided below the shaft 120. The balancing weight mechanism 130 is adapted to provide same pressing force on the fabric 10 being wound. However, the provision of friction mechanisms 110 and balancing weight mechanism 130 may inevitably increase the manufacturing cost and complicate the components of the fabric take-up apparatus 100. Thus, the need for improvement still exists.

High-speed high-stand fabric take-up device with uniform fabric tautness arrangement


A communication control apparatus detects a predetermined signal type in accordance with SMTP protocol from a first interface section connected to an IFAX. The communication control apparatus controls communication with the IFAX in accordance with the SMTP protocol when the predetermined signal type is detected. On the other hand, the communication control apparatus controls communication with a server via a second interface section connected to a network, to which the IFAX is connected. The network is managed by the server. The communication control apparatus receives email data from the IFAX, converts it into HTML data, and transmits the HTML data to the server. Accordingly, the communication control apparatus is capable of enabling the IFAX to operate on the network managed by a HTTP protocol.

1. Field of Invention
The present invention relates to a communication control apparatus connected between an Internet facsimile apparatus and a network, that controls communication between the Internet facsimile apparatus and the network, and a communication control method.
2. Description of Related Art
Conventionally, a network using groupware software is set up in order to share information effectively within an organization such as a company. Recently, Internet technology has become common and groupware software usable from a www browser are very often used in such a network (hereafter referred to as "groupware network"). In this case, client terminals such as PCs on the groupware network can share information on the groupware network using the www browser. Therefore, the client terminals can provide features such as email and electronic bulletin boards.
On the other hand, a facsimile apparatus, which can transmit image information via the Internet by the same operation as a conventional facsimile apparatus, has been recently developed. This type of facsimile apparatus is called an Internet facsimile apparatus(hereafter referred to as IFAX) because it uses Internet for a part or all of the transmission path.
When image data is transmitted, such an IFAX device converts facsimile data into email format to transmit. On the other hand, when IFAX receives image information, it converts email data into facsimile format and executes a printing process. At this time, the email data communication of the IFAX is controlled in accordance with SMTP (Simple Mail Transfer Protocol) or POP3 (Post Office Protocol Version3).
However, communication of various kinds of data are performed using HTTP protocol in the groupware network using a www browser, as mentioned above. Therefore an IFAX that controls communication in accordance with SMTP (Simple Mail Transfer Protocol) or POP3 (Post Office Protocol Version 3) cannot be provided.

Communication control apparatus and a communication control method


A stick ignition coil apparatus for an ignition plug includes a primary coil arrangement, a secondary coil arrangement, a center core, a coil case, a high voltage terminal, a spring case and dielectric resin. The primary coil arrangement is located radially outward of the secondary coil arrangement, which is located radially outward of the center core. The coil case is located radially outward of the primary coil arrangement. The high voltage terminal is located at a distal end of the secondary coil arrangement. The spring case holds a spring. The dielectric resin is filled in a space defined radially inward of the coil case. An open end of the high voltage terminal is connected to an annular corner portion of a distal projecting portion of a secondary spool of the secondary coil.

1. Field of the Invention
The present invention relates to a stick ignition coil apparatus for an internal combustion engine.
2. Description of Related Art
A stick ignition coil apparatus includes a center core, an outer core, a primary coil arrangement and a secondary coil arrangement. By switching on and off of supply of an electric current to the primary coil arrangement, a high voltage is generated in the secondary coil arrangement. The high voltage, which is generated at the secondary coil arrangement, is supplied to an ignition plug by way of a high voltage terminal, which is located at a (lower) end of the secondary coil arrangement.
As shown in FIG. 23A, a conventional stick ignition coil apparatus has a coil case 300, which includes a center core 302, a secondary coil arrangement 304, which is located radially outward of the center core 302, and a primary coil arrangement 308, which is located radially outward of the secondary coil arrangement 304. The secondary coil arrangement 304 includes a secondary spool 305 and a secondary winding 306, which is wound around the secondary spool 305. The primary coil arrangement 308 includes a primary spool 309 and a primary winding 310, which is wound around the primary spool 309.
A terminal plate (a second terminal element) 317, which is shaped into a tubular form, is installed at a bottom end of the secondary spool 305. A tubular-form high voltage terminal (a first terminal element) 315, an opening of which faces downward, is held in a spring case 312, which holds a spring 313. The spring 313 is located between the high voltage terminal 315 and the ignition plug (not shown). An upwardly extending portion of the high voltage terminal 315 contacts the terminal plate 317. Therefore, a bottom end of the secondary winding 306 is connected with the ignition plug, by way of the terminal plate 317, the high voltage terminal 315 and the spring 313. A space, which is formed by a bottom end of the coil case 300, the spring case 312, the high voltage terminal 315 and the like, is filled with dielectric resin 319 (see Unexamined Japanese Patent Publication No. 2000-133534).
However, in the above-described conventional art, a crack may be formed on the dielectric resin 319. Here, the terminal plate 317, which is a copper alloy, such as phosphor bronze, does not adhere well to the dielectric resin 319, which is made of a thermosetting epoxy resin. Furthermore, a coefficient of linear thermal expansion of the terminal plate 317 differs from that of the dielectric resin 319. Therefore, as shown in FIG. 23B, when a thermal stress is generated in a radial direction at the time of starting and stopping of an engine, and the crack tends to be formed at a phase boundary 321 between the terminal plate 317 and the dielectric resin 319.
An edge effect of the terminal plate 317 is added to the crack at the phase boundary. This means that the thermal stress is concentrated around an edge 317a and a resin portion therearound. Then, the dielectric resin 319 gets the crack 322, which starts from the edge 317a of the terminal plate 317. This may cause a dielectric breakdown.

Stick ignition coil apparatus for ignition plug


An image processing device includes a storing section configured to store a predetermined dither mask, a defective nozzle detecting section configured to detect a defective nozzle, and an interpolation processing section configured to specify a mask position corresponding to a position of the detected defective nozzle among mask positions included in the dither mask, and alter a threshold of a predetermined mask position so that a dot of the predetermined mask position included in the dither mask becomes ON when a dot of the specified mask position is ON.

1. Technical Field
The present invention relates to an image processing device, a dither mask generation method, and a program.
2. Related Art
In a printer such as an inkjet printer, etc., an ink ejection cannot be sometimes performed by an occurrence of clogging with ink in an ink nozzle. In this regard, JP-A-2004-202795 (Patent Document 1) discloses that dither processing is performed by selecting one dither mask among a plurality of dither masks so that a dot on a line corresponding to a non-ejection nozzle among image data becomes non-ejection. In the selected dither mask, a threshold is set so that a gradation can be expressed at normal ejection positions other than non-ejection positions.

Image processing device, dither mask generation method, and program


Methods, apparatus, and systems for performing fault diagnosis are disclosed herein. In one exemplary embodiment, a failure log is received including entries indicative of compressed test responses to chain patterns and compressed test responses to scan patterns. A faulty scan chain in the circuit-under-test is identified based at least in part on one or more of the entries indicative of the compressed test responses to chain patterns. One or more faulty scan cell candidates in the faulty scan chain are identified based at least in part on one or more of the entries indicative of the compressed test responses to scan patterns. The one or more identified scan cell candidates can be reported. Computer-readable media comprising computer-executable instructions for causing a computer to perform any of the disclosed methods are also provided. Likewise, computer-readable media storing lists of fault candidates identified by any of the disclosed methods are also provided.

The accurate diagnosis of faults is an increasingly important aspect of testing integrated circuits, especially in view of ever-increasing gate counts and shrinking feature sizes. For circuits that do not utilize compression techniques during testing, fault diagnosis is relatively straightforward. For circuits that have embedded compression hardware, however, accurate fault diagnosis presents a formidable challenge.
The use of compression during the testing of integrated circuits has become widespread. In general, compression helps reduce the volume of test data required for even traditional stuck-at test sets. Such sets, for example, often exceed the capacity of automatic test equipment ("ATE") used to test today's multimillion-gate integrated circuits. Moreover, due to the limited bandwidth between the circuit-under-test ("CUT") and the ATE, the use of compressed test data and compressed test responses can decrease test time, and thus the test cost.
Automated fault diagnosis (e.g., diagnosis based on chain patterns and scan patterns obtained from automated test pattern generation ("ATPG")) is a desirable component of an overall failure-analysis process. Automated fault diagnosis is generally used to predict the location of a failure in a CUT and has applications in such fields as silicon debugging, yield learning, and yield improvement. Given the failing test responses to a test set, an automated fault diagnosis tool desirably identifies the suspect fault sites that best explain the failures. The suspect sites identified can help locate the physical cause of the fault and be used to guide failure analysis at the physical level.

Compactor independent direct diagnosis of test hardware


A rail unit comprises a fixed rail, a movable rail slidably engaged with the fixed rail and a locking mechanism for locking the movable rail relative to the fixed rail. In order to increase a mechanical strength of a given part of lower flanges of the movable rail where locking openings for the locking mechanism are formed, the given part is integrally formed at an upper end thereof with a raised portion, or the lower flanges of the movable rail are formed at mutually mating portions with depressed portions. When the movable rail and the fixed rail are subjected to a mutually pulled apart movement upon a vehicle collision of the like, the raised portion or the depression portions are brought into abutment with an inner surface of the fixed rail to suppress or at least minimize deformation of the rail unit.

1. Field of the Invention
The present invention relates in general to automotive seat slide devices, and more particularly to automotive seat slide devices of a type which is equipped with reinforcing means for assuring or keeping a locked connection between fixed and movable rails upon a vehicle collision or the like.
2. Description of the Prior Art
In automotive seat slide devices, there is a type which comprises two, viz., right and left rail units each including a fixed rail which is secured to a vehicle floor and a movable rail which is slidably engaged with the fixed rail and carries thereon a seat. At least one of the two rail units is equipped with a position lock mechanism for locking the movable rail at a desired fore-and-aft position relative to the fixed rail.
In order to clarify the task of the present invention, one conventional automotive seat slide device of the above-mentioned type will be described with reference to FIGS. 14 to 17 of the accompanying drawings. The conventional seat slide device shown in the drawings is disclosed in Japanese Utility Model First Provisional Publication 3-53331.
Referring to FIG. 15, there is shown one (viz., right one) of two rail units of the known seat slide device.
As shown in the drawing, the rail unit 1 comprises a fixed rail 3 which is secured to a floor of a motor vehicle, a movable rail 4 which is slidably engaged with the fixed rail 3 and a position lock mechanism 5 which can lock the movable rail 4 at a desired fore-and-aft position relative to the fixed rail 3.
The fixed rail 3 has a generally U-shaped cross section and has an axially extending slit 2 defined between two inward upper flanges 8a and 8b. One of side walls of the fixed rail 3 is formed with a plurality of aligned locking openings 17 which constitute part of the position lock mechanism 5, as will become apparent hereinafter. A bottom surface of the fixed rail 3 is denoted by numeral 7.
The movable rail 4 has a reversed T-shaped cross section and has a vertical wall portion 6 received in the slit 2 and two lower flanges 10a and 10b received in the fixed rail 3. As shown, the movable rail 4 is constructed of two metal plates which are combined in a back-to-back connecting manner. The movable rail 4 comprises the vertical wall portion 6 whose upper end is secured to a seat (not shown) and the two lower flanges 10a and 10b which extend in laterally opposite directions and have leading end portions 19a and 19b bent upward.
As is seen from FIGS. 15, 16 and 17, one of the lower flanges 10a and 10b of the movable rail 4, that is, the flange 10b, is formed with three aligned locking openings 18 each extending to the upwardly bent portion 19b. As is understood from FIG. 15, the lower flange 10b in which the locking openings 18 are formed is the flange which is directed toward the side wall of the fixed rail 3 where the aligned locking openings 17 are formed. The three locking openings 18 constitute part of the position lock mechanism 5, as will become apparent hereinafter.
As may be understood from FIG. 15, rollers (not shown) are disposed on the bottom surface 7 of the fixed rail 3, which rotatably support the two lower flanges 10a and 10b of the movable rail 4, and balls (not shown) are rotatably disposed in two chamber structures each being defined by one inward upper flange 8a or 8b of the fixed rail 3 and one lower flange 10a or 10b of the movable rail 4. With these rollers and balls, the sliding movement of the movable rail 4 relative to the fixed rail 3 is smoothly carried out.
The position lock mechanism 5 comprises a holder plate 12 which is welded to the vertical wall portion 6 of the movable rail 4. The holder plate 12 has a curled supporting portion 13 by which a control rod 14 is rotatably supported. A latch plate 15 having three pawls 16 is secured to the control rod 14 to rotate or pivot therewith.
As is understood from FIG. 15, when the movable rail 4 is slid to a position where the three locking openings 18 of the movable rail 4 are registered with three of the locking openings 17 of the fixed rail 3, the three pawls 16 of the latch plate 15 can enter the registered three pairs of locking openings 17 and 18 to achieve locking between the movable and fixed rails 4 and 3. That is, under this condition, the movable rail 4 is locked at the position relative to the fixed rail 3. Although not shown in the drawings, a biasing spring is incorporated with the control rod 14 to bias the same in a locking direction, that is, in a direction to bias the three pawls 16 of the latch plate 15 toward the locking openings 17 and 18. Thus, when the movable rail 4 is slid to such a registered position, the three pawls 16 of the latch plate 15 are automatically led into the three pairs of the locking openings 17 and 18 to achieve the locking of the movable rail 4.
In this locked condition, the pawls 16 of the latch plate 15 are engaged with not only the locking openings 17 of the fixed rail 3 but also the locking openings 18 of the movable rail 4, and thus a so-called center impelling supporting is effected by each pawl 16. Accordingly, much assured locking is obtained as compared with a locking of a type wherein the pawls 16 are engaged with only the locking openings 17 of the fixed rail 3.
However, the above-mentioned seat slide device 1 has the following drawback due to inherent construction of the lower flange 10b of the movable rail 4.
That is, as is understood from FIGS. 14 and 16, the upwardly bent portion 19b of the lower flange 10b of the movable rail 4 fails to have a robust structure due to provision of the three locking openings 18. More specifically, an apertured part 20 of the upwardly bent portion 19b where the three locking openings 18 are formed fails to have a robust structure. In fact, each locking opening 18 extends close to the top of the upwardly bent portion 19b, which reduces the effective thickness "H" of the portion 19b. Thus, when, due to a vehicle collision or the like, a great force is suddenly applied to the upwardly bent portion 19b through the three pawls 16 of the latch plate 15, such bent portion 19b tends to be severely deformed affecting the center impelling supporting by the pawls 16 by a certain degree. Although usage of a thicker or high rigidity metal plate as a material of the movable rail 4 can eliminate such drawback, weight and cost of the seat slide device are inevitably increased.


A method and system for applying therapeutic electrical pulses to the heart includes a plurality of spaced apart electrodes. Each electrode in electrical communication with a pulse generator and are operative to deliver at least one energy pulse to a patient's heart. Sensors and electrical communication with a controller are operative to detect an abnormal rhythm in the patient's heart and transmit a signal to a controller to indicate an abnormal rhythmic condition. The controller is configured to receive the abnormal rhythmic signal from the sensor and cause the pulse generator to emit a sequence of spatially and temporally distinct pulses through the electrodes, each pulse passing through at least one of the electrodes.

A variety of physiological conditions exist where irregular electrical activity of a heart results in an abnormal heartbeat. To correct the abnormal heartbeat, a multiplicity of systems and methods have been developed whereby at least one therapeutic electrical shock or pulse is applied to the heart through one or two electrodes to disrupt the irregular electrical activity so that the heart may revert to its regular electrical activity, resulting in a normal heartbeat.
Such systems and methods utilize electrical field stimulation wherein a sufficiently large shock is applied to the heart through one or two electrodes to produce a desired extracellular potential gradient in large regions of the heart distant from the electrodes. In this manner, the irregular electrical activity throughout the heart is sufficiently disrupted to permit restoration of normal electrical activity and normal heartbeat.
Many prior art systems and methods first detect, through a variety of known devices, a rhythmic condition such as tachycardia (relatively rapid heart action), arrhythmia (an alteration in the rhythm of the heartbeat either in time or force), tachyarrhythmia (arrhythmia characterized by a rapid, irregular heartbeat), and atrial or ventricular fibrillation (very rapid uncoordinated constrictions of the atria or ventricle, respectively, resulting in loss of the ability to pump blood, most particularly in the case of ventricular fibrillation). Next, an electrical shock is applied to the heart through one or two electrodes positioned on or within the heart. The electrical shock applied to the heart through the electrodes is large enough to produce an electric field in regions of the heart near and remote from the electrodes. Selected prior art systems include feedback mechanisms whereby the electrical condition of the heart is detected subsequent to the application of the first shock and, if a normal heart rhythm is not restored, an additional electrical shock is applied to the heart.
Measurements have recently been obtained utilizing optical mapping techniques with voltage-sensitive fluorescent dyes in hearts which indicate that the effects of an electrical stimulation pulse on the transmembrane potential of heart cells are greatest in the region within one millimeter of the stimulation electrode.
Because the strength of an electric field decreases with increasing distance from the electrodes, a pulse which produces an electric field sufficient for defibrillation in a region remote from an electrode will produce a much stronger electric field near the electrode. Injuries are produced in heart cells by such strong electrical stimulation when, during the electrical pulse, the transmembrane potential exceeds the threshold for cell membrane electroporation. As prior art cardioversion and defibrillation systems require the application of high voltage pulses to the heart to produce an electric field in regions of the heart remote from the electrodes, such systems also have large energy requirements.
One method, disclosed in U.S. Pat. No. 4,708,145 to Tacker, Jr. et al. attempts to avoid areas of high current density in the heart by using a sequential pulse, multiple pathway defibrillation method for controlling ventricular fibrillation and tachyarrhythmias. A catheter carrying a first and second electrode is located in the right ventricle and a third electrode is located either at the chest wall or at the abdominal cavity. The second and third electrodes are sequentially paired and pulsed with the first electrode to control ventricular fibrillation and other tachyarrhythmias. While the Tacker, Jr. et al device applies shocks to the heart through spaced apart electrodes, these shocks are intended to traverse the heart through particular pathways to establish a sufficient electric field in regions of the heart remote from the electrodes.
Since the effects of electrical shocks on transmembrane potentials are large near an electrode, a system to produce effects primarily in the cells near an electrode could require stimulation voltage or current that is less than the voltage or current needed to produce a desired electric field remote from an electrode. Such a system would require low current pulses which could decrease both the system energy requirements and cellular damage resulting from each electrical pulse. Low strength stimulation at a single site is already known to effect arrhythmias and even, as reported by Salama, halt ventricular tachycardia in isolated rapid hearts when applied to Purkinje fibers which occur on the endocardium.
Although the prior art provides a variety of cardioversion and defibrillation methods and systems, there remains a need for a method and system for cardioversion of a heart which utilizes low voltage pulses which minimizes damage to the heart with low power requirements.

System and method for cardioversion using scan stimulation