Provided herein are methods and compositions for performing multiplex RT-PCR to amplify short nucleic acids.

Non-invasive sample collection (e.g., blood, plasma, saliva, urine) is becoming more common, encouraged by ease and reduced cost of sample collection. Nucleic acid biomarkers in liquid biopsies are often short, e.g., less than 250 nucleotides in length. Examples of disease associated biomarkers in liquid biopsies are miRNA molecules, several of which have been found at abnormal levels in various disease states. miRNA molecules are typically 16-30 nucleotides in length.
Biomarker nucleic acids are typically quite rare in a liquid biopsy, so amplification of the biomarker nucleic acid is advantageous to increase sensitivity of detection. Specific amplification of short nucleic acid sequences, however, is challenging. Amplification primers are often in the range of 15-25 nucleotides, and shorter complementary sequences can result in reduced specificity. Thus, while amplification and detection techniques typically require two primers and a probe, each of these elements can be about the same size as the targeted nucleic acids in a liquid biopsy.
One approach to amplification and detection of short nucleic acid sequences is disclosed in WO2016027162. This document discloses RT-qPCR detection of miRNA and other short nucleic acids using a two-tailed reverse transcription (RT) primer. The previously disclosed two-tailed primer is designed for detection of one miRNA per RT and PCR well, and uses target-specific forward and reverse PCR primers.
For many diagnostic applications it is desirable to monitor levels of more than one biomarker, as well as external and/or internal controls for each sample. The present disclosure provides novel compositions and methods for specific multiplex amplification and detection of short nucleic acids.

Multiplex detection of short nucleic acids


The present invention is directed to compositions for use as additives in the automotive industry, which compositions contain waste powder prime and a plasticizer selected from the group consisting of 2-ethylhexyl diphenyl phosphate, diisoheptyl phthalate, a linear phthalate based upon C7-C9 alcohols, a mixture of esters containing a minimum of 55 percent of diesters and a maximum of 20 percent dibenzoate, a mixture of esters containing a minimum of 60 percent of diesters and a maximum of 30 percent dibenzoate and dipropylene glycol dibenzoate and automotive sealants which contain waste powder prime, a plasticizer selected from the group consisting of 2-ethylhexyl diphenyl phosphate, diisoheptyl phthalate, a linear phthalate based upon C7-C9 alcohols, a mixture of esters containing a minimum of 55 percent of diesters and a maximum of 20 percent dibenzoate, a mixture of esters containing a minimum of 60 percent of diesters and a maximum of 30 percent dibenzoate and dipropylene glycol dibenzoate and automotive sealants; and a polymeric resin.

The invention relates to compositions which may be used in the automotive industry, particularly as additives in the preparation of automotive sealants.
In the manufacture of automobiles, the bodies and frame assemblies thereof are coated, or primed, electrostatically with a 100 percent solids powder spray. The compositions of such powder sprays, referred to in the automotive industry as xe2x80x9cpowder primexe2x80x9d, and methods of electrostatically applying the powder prime are well known to those skilled in the automotive industry. It is estimated that on the order of 25,000 pounds per month of 100 percent solids waste powder prime may be generated at each assembly plant in which it is used to prime auto parts, such as frame assemblies. The waste powder prime, that prime which does not remain affixed to the primed auto part and which is recovered subsequent to the electrostatic deposition of the powder prime thereon, currently is being transported to landfills for disposal. It would be considered to be a significant environmental advance and contribution if one were to discover a use of waste powder prime, such that the present practice of disposing of waste powder prime in landfills could be reduced significantly, or totally eliminated.
Also in the manufacture of automobiles, automotive sealants are used in order to prevent air, water and dust intrusion into the passenger compartment of the automobile. These sealants typically are made of plastisols, those being mixtures of plasticizers and polymeric resins such as poly(vinyl chloride), poly(vinyl acetate), or copolymers of vinyl chloride and vinyl acetate. Other polymers may be used as well in preparation of the plastisols. The sealants further may contain ingredients such as fillers, for instance calcium carbonate, talc, calcium oxide, and glass hollowspheres; rheological additives such as thixotropes, for instance silicas and clay derivatives, and pigments, for instance titanium dioxide and carbon black. Because the adhesion of a plastisol to cold-rolled-steel or electrodeposition coatings (E-coat) is poor, conventional sealants must contain adhesion promoters. The most common of the adhesion promoters used in preparation of the sealants is polyamidoamines. Without the adhesion promoters, such sealants will exhibit poor adhesion to such substrates as cold rolled steel and the E-coat.
It has been reported that waste paint sludge which is recovered from automotive xe2x80x9cpaintingxe2x80x9d processes and which contains water, solvent and uncured polymer, may be used in the preparation of automotive sealants. However, before the waste paint sludge may be used to prepare automotive sealants, the waste paint sludge must undergo extensive treatment and processing to remove all or most of the water or solvent from the waste sludge. The xe2x80x9cpaintingxe2x80x9d operations from which the waste sludge is recovered differ from the xe2x80x9celectrostatic depositionxe2x80x9d from which the waste powder prime is recovered. The powder prime never contains water or solvent, either as a virgin material or as a waste material. Additionally, the powder prime does not utilize ingredients such as tackifiers, plasticizers and coalescents, which commonly are used in film-forming xe2x80x9cpaintsxe2x80x9d formulated with water and/or solvents.
The present inventors surprisingly have discovered that waste powder prime may be used, without further recycling or treatment, in order to formulate compositions which may be used in the automotive industry. Specifically, the inventors surprisingly have discovered that waste powder prime may be used in combination with specific plasticizers in order to prepare compositions which may be used as additives in the automotive industry. In particular, the additives are used in the preparation of automotive sealants.
The inventors can identify at least three distinct advantages of their invention over the prior art paint sludge. First, the waste powder prime requires no processing to remove unwanted solvent or water prior to its use in the preparation of automotive sealants. Second, the waste powder prime typically is free or essentially free of components such as tackifiers, plasticizers and coalescents, which commonly are used in film-forming xe2x80x9cpaintsxe2x80x9d formulated with water and/or solvents. As a result, in the formulation of compositions which utilize waste powder prime, the formulator need not be concerned with detrimental affects such components might have on the particular formulated compositions. Finally, the present invention provides a practical and economical solution to a significant environmental need by reducing or eliminating the amount of waste powder prime which is disposed of in landfills, without the need for extensive and expensive recycling processes, while unexpectedly providing improvements in automotive compositions which have not been reported heretofore. It is believed that each of the above advantages in and of itself constitutes a significant improvement over the prior art xe2x80x9cpaint sludgexe2x80x9d containing water and solvent, as discussed above. In addition to the fact that all three of the above advantages may be realized simultaneously, the compositions of the present invention offer other advantages which are disclosed herein below.
The present invention is directed to compositions which may be used as additives in the automotive industry, which compositions comprise waste powder prime (WPP) and a plasticizer selected from the group consisting of 2-ethylhexyl diphenyl phosphate, diisoheptyl phthalate, a linear phthalate based upon C7-C9 alcohols, a mixture of esters, and dipropylene glycol dibenzoate. When used as an additive, in the preparation of formulated automotive sealants which are substantially free of an adhesion promoter, or preferably which are free of an adhesion promoter, the inventive additives provide sealants which exhibit adhesion which is as good as or better than conventional automotive sealants which do contain an adhesion promoter in conventional amounts used to provide adhesion to automotive sealants. Also included within the scope of the present invention are automotive sealant compositions which comprise a polymeric resin, WPP and a plasticizer selected from the group consisting of 2-ethylhexyl diphenyl phosphate, diisoheptyl phthalate, a linear phthalate based upon C7-C9 alcohols, a mixture of esters, and dipropylene glycol dibenzoate.

Automotive additives and sealants containing waste powder prime


The coated superelastic stent is formed from a tube of collagen having an inner structure of a micro-cable made of strands of a material exhibiting super-elasticity or shape memory properties, such as nickel-titanium, and includes a strand of radiopaque material, such as platinum or gold, in order to provide a radiopaque marker during interventional therapeutic treatment or vascular surgery. The collagen tube can be loaded with a therapeutic agent for treatment of the desired site in the vasculature.

1. Field of the Invention
This invention relates generally to implantable devices for interventional therapeutic treatment or vascular surgery, and more particularly concerns a coated superelastic stent formed from a stranded micro-cable with enhanced radiopacity.
2. Description of Related Art
The art and science of interventional therapy and surgery has continually progressed towards treatment of internal defects and diseases by use of ever smaller incisions or access through the vasculature or body openings in order to reduce the trauma to tissue surrounding the treatment site. One important aspect of such treatments involves the use of catheters to place therapeutic devices at a treatment site by access through the vasculature. Examples of such procedures include transluminal angioplasty, placement of stents to reinforce the walls of a blood vessel or the like and the use of vasoocclusive devices to treat defects in the vasculature. There is a constant drive by those practicing in the art to develop new and more capable systems for such applications. When coupled with developments in biological treatment capabilities, there is an expanding need for technologies that enhance the performance of interventional therapeutic devices and systems.
One specific field of interventional therapy that has been able to advantageously use recent developments in technology is the treatment of neurovascular defects. More specifically, as smaller and more capable structures and materials have been developed, treatment of vascular defects in the human brain which were previously untreatable or represented unacceptable risks via conventional surgery have become amenable to treatment. One type of nonsurgical therapy that has become advantageous for the treatment of defects in the neurovasculature has been the placement by way of a catheter of vasoocclusive devices in a damaged portion of a vein or artery.
Vasoocclusion devices are therapeutic devices that are placed within the vasculature of the human body, typically via a catheter, either to block the flow of blood through a vessel making up that portion of the vasculature through the formation of an embolus or to form such an embolus within an aneurysm stemming from the vessel. The vasoocclusive devices can take a variety of configurations, and are generally formed of one or more elements that are larger in the deployed configuration than when they are within the delivery catheter prior to placement. One widely used vasoocclusive device is a helical wire coil having a deployed configuration which may be dimensioned to engage the walls of the vessels. One anatomically shaped vasoocclusive device that forms itself into a shape of an anatomical cavity such as an aneurysm and is made of a preformed strand of flexible material that can be a nickel-titanium alloy is known from U.S. Pat. No. 5,645,558, which is specifically incorporated by reference herein.
The delivery of such vasoocclusive devices can be accomplished by a variety of means, including via a catheter in which the device is pushed through the catheter by a pusher to deploy the device. The vasoocclusive devices, which can have a primary shape of a coil of wire that is then formed into a more complex secondary shape, can be produced in such a way that they will pass through the lumen of a catheter in a linear shape and take on a complex shape as originally formed after being deployed into the area of interest, such as an aneurysm. A variety of detachment mechanisms to release the device from a pusher have been developed and are known in the art.
For treatment of areas of the small diameter vasculature such as a small artery or vein in the brain, for example, and for treatment of aneurysms and the like, micro-coils formed of very small diameter wire are used in order to restrict, reinforce, or to occlude such small diameter areas of the vasculature. A variety of materials have been suggested for use in such micro-coils, including nickel-titanium alloys, copper, stainless steel, platinum, tungsten, various plastics or the like, each of which offers certain benefits in various applications. Nickel-titanium alloys are particularly advantageous for the fabrication of such micro coils, in that they can have super-elastic or shape memory properties, and thus can be manufactured to easily fit into a linear portion of a catheter, but attain their originally formed, more complex shape when deployed. Although various materials are more or less kink resistant when nickel-titanium alloys are dimensioned into wire smaller than approximately 0.010 inches in diameter, they can have low yield strength and can kink more easily, thus severely limiting the applications for such finely drawn wire in the fabrication of vasoocclusive devices. As a further limitation to such applications, nickel-titanium alloys are also not radiopaque in small diameters, and a single nickel-titanium wire would need to be approximately 0.012 inches in diameter to be even slightly radiopaque. However, such a thickness of a single nickel-titanium wire would unfortunately also be relatively stiff and possibly traumatic to the placement site, particularly if used for treatment of delicate and already damaged areas of the small diameter vasculature such as an aneurysm in an artery or vein in the brain, for example.
One conventional guidewire for use in a catheter is known that is made of a high elasticity nickel-titanium alloy, and is useful for accessing peripheral or soft tissue targets. The distal tip of the guidewire is provided with a radiopaque flexible coil tip, and a radiopaque end cap is attached to the guidewire by a radiopaque ribbon. Such a construction is complex to manufacture, fragile and can potentially break off during use with undesirable results. A stretch resistant vasoocclusive coil is also known that can be made of a primary helically wound coil of platinum wire, with a stretch-resisting wire attached within the primary coil between two end caps. Unfortunately, such a construction is relatively difficult to fabricate and also fragile, allowing for the possibility of the fracture of the central radiopaque wire, the coil, the welds or some combination of them, and it can also potentially break off during use. Also, such a construction has a complex and nonlinear bending characteristic, dependent on the spacing of the coils and central wire and the radius of the bend of the coil.
Stents are typically implanted within a vessel in a contracted state and expanded when in place in the vessel in order to maintain patency of the vessel, and such stents are typically implanted by mounting the stent on a balloon portion of a balloon catheter, positioning the stent in a body lumen, and expanding the stent to an expanded state by inflating the balloon. The balloon is then deflated and removed, leaving the stent in place. However, the placement, inflation and deflation of a balloon catheter is a complicated procedure that involves additional risks beyond the implantation of the stent, so that it would be desirable to provide a stent that can be more simply placed in the site to be treated in a compressed state, and expanded to leave the stent in place.
Stents also commonly have a metallic structure to provide the strength required to function as a stent, but typically do not provide for the delivery of localized therapeutic pharmacological treatment of a vessel at the location being treated with the stent. Stents formed of polymeric materials capable of absorbing and releasing therapeutic agents may not provide adequate structural and mechanical requirements for a stent, especially when the polymeric materials are loaded with a drug, since drug loading of a polymeric material can significantly affect the structural and mechanical properties of the polymeric material. Since it is frequently desirable to be able to provide localized therapeutic pharmacological treatment of a vessel at the location being treated with the stent, it would be desirable to combine such polymeric materials with a stent structure to provide the stent with the capability of absorbing and delivering therapeutic drugs or other agents at a specific site in the vasculature to be treated.
Conventional forms of stents are known that have a covering or outer layers of collagen, that can be used for enhancing biocompatability and for drug delivery. One known tubular metal stent, for example, is combined with a covering sleeve of collagen in order to increase the biocompatibility of the stent upon implantation. The collagen sleeve may be collagen per se or a collagen carried on a support of Dacron or a similar material. Another three-layer type of vascular prosthesis has two outer layers formed of collagen, and a middle layer made from inert fibers such as synthetic fibers. Another tubular reinforcing structure for use as a cardiovascular graft is made of collagenous tissue with a reinforcing fibrous structure surrounding the lumen. One drug delivery collagen-impregnated synthetic vascular graft is also known, formed from a porous synthetic material having collagen such that the graft substrate cross-links the collagen in order to render the substrate blood-tight. A matrix is also provided in another biodegradable drug delivery vascular stent that is made from collagen or other connective proteins or natural materials that can be saturated with drugs. However, none of these types of stents provide for a coated, superelastic shape memory stent that can be delivered and released at the site in the vasculature to be treated in a compressed state, and expanded to leave the stent in place without the need for placement with a balloon catheter.
From the above, it can be seen that vasoocclusive devices and stents provide important improvements in the treatment of the vasculature. However, it would be desirable to provide a structural element that used to form a coated stent, that offers the advantages of a shape memory alloy such as a nickel-titanium alloy, and that incorporates radiopaque material in a stable configuration that is not subject to breaking during use of the device, so that the device can be visualized under fluoroscopy. The present invention meets these and other needs.
Significant advances have been made in the treatment of neurovascular defects without resolution to surgery. More specifically, micro catheters have been developed which allow the placement of vasoocclusive devices in an area of the vasculature which has been damaged. In presently used techniques, the vasoocclusive devices take the form of spiral wound wires that can take more complex three dimensional shapes as they are inserted into the area to be treated. By using materials that are highly flexible, or even super-elastic and relatively small in diameter, the wires can be installed in a micro-catheter in a relatively linear configuration and assume a more complex shape as it is forced from the distal end of the catheter.
In order to gain the advantages presently being realized with micro-catheter therapies and procedures to repair damage to the vasculature in the brain and other vessels, shape memory materials such as nickel-titanium alloys have been incorporated in vasoocclusive devices to be placed by the catheters. However, the range of diameters of wire and the configurations of the resulting geometry of both the coils and the devices developed which can be used have been limited by both the relatively small diameter of wire that must be used to avoid trauma and allow housing within the catheter prior to deployment, and the requirement for larger diameters to provide for radiopaque markers and mechanical robustness. In many cases this has resulted in primary wire characteristics in the coil that are unacceptably stiff, very delicate, or subject to kinking. The present invention obtains significant advantages over such prior art devices by providing a cable of multiple strands of an alloy adapted to be used in catheters, stents, vasoocclusive devices, guidewires and the like, thus providing a kink resistant, high strength material with highly desirable performance characteristics which can be altered by construction details to suit a variety of interventional therapeutic procedures.
More specifically, it has been found that single strands of small diameter nickel-titanium alloys, as well as other metal alloys, used to form vasoocclusive devices can be kinked if twisted and pulled as can occur during or after deployment from a catheter, especially if the doctor wishes to withdraw a partially deployed coil because it is somehow incorrect in size, shape or length to repair the damage to the vessel. Also, single wire coils are more likely to cause trauma to the area to be treated if the wire is of a sufficient diameter to provide adequate tensile strength. Furthermore, such small diameter wires of some of these materials such as nickel-titanium, stainless steel and the like, are not generally radiopaque with currently available equipment, necessitating the use of radiopaque markers attached to the device, with the resultant possible diminution of functionality and increased diameter.
The present invention solves these and other problems by providing, in its broadest aspect, a superelastic collagen coated stent formed from a micro-cable which includes at least one radiopaque strand to offer a continuous indication under fluoroscopy of the deployed configuration of the device incorporating the micro-cable. When combined with the benefits of a material such as nickel-titanium in the other strands of the micro-cable, numerous advantages are available from the use of this basic construction in interventional medicine. The shape of the superelastic collagen coated stent can contour to the shape of the anatomical cavity or portion of the vasculature, and the superelastic collagen coated stent would provide an adequate surface area of collagen for contact with a vessel wall to deliver drugs to the vessel wall.
Briefly, and in general terms, a presently preferred embodiment of the present invention provides for a superelastic collagen coated stent formed from a multi-stranded micro-cable made of a suitable material such as stainless steel or a nickel-titanium alloy, with the cable including at least one radiopaque strand, made of platinum, tungsten or gold, in order to serve as a marker during a procedure. The multi-stranded micro-cable can be configured into a stent to reinforce areas of the small diameter vasculature such as an artery or vein in the brain, for example. The superelastic collagen coated stent can be formed as a helical ribbon or tape, supported internally by a superelastic structure that can be compressed along the width and length of the stent structure, to be pushed by a pusher member through a microcatheter or cannula. When deployed in a helical configuration, with a ribbon cross-section, a closed helical pitch is achieved, providing a collagen tube in contact with the vessel wall. The stent is detachable from the pusher member. The superelastic collagen coated stent can be manufactured by producing the superelastic inner structure, compressing the structure, sliding it into a collagen tube, and allowing the superelastic inner structure to expand and flatten the tube into a ribbon. The collagen tube of the superelastic collagen coated stent is preferably loaded with a therapeutic agent or drug to reduce or prevent restenosis and thrombosis in the vessel being treated.
In one presently preferred embodiment, the invention accordingly provides for a superelastic collagen coated stent formed from a multi-stranded micro-cable having a plurality of flexible strands of a super elastic material, and at least one radiopaque strand. In one presently preferred embodiment, the multi-stranded micro-cable comprises a plurality of flexible strands of nickel-titanium alloy, the micro-cable having at least one central axially disposed radiopaque wire, such as platinum, tungsten or gold, for example, in order to provide a radiopaque marker during vascular procedures. In this preferred embodiment, the construction of the invention places the lowest tensile strength and highest flexibility member, the radiopaque marker strand, in a position in the cable which results in minimum stress on that member; at the same time, the superelastic material is in the outer strands, which have the dominant affect on performance parameters, thus enhancing the benefits of the material. Another benefit associated with the invention compared to prior art devices is that the multiple stranded cable configuration, in addition to providing a highly flexible and resilient structure, eliminates the necessity of a safety wire, since the failure of a single strand will not cause a severing of the cable. Also, the construction prevents stretching of the cable in the event of failure of a single strand, which is a significant benefit compared to constructions which have a coil around a central safety wire.
In a second presently preferred embodiment, the invention includes a superelastic collagen coated stent formed from a multi stranded cable constructed of multiple twisted strands of a suitable material such as a shape memory alloy or super elastic alloy of nickel-titanium, with one or more of the twisted strands consisting of a radiopaque material. The radiopaque strand may be one or more of the peripheral twisted strands and may also include one or more central strands of the cable. In a preferred aspect of the embodiment, the cable consists of six peripheral twisted strands and a central linear core strand, one or more of which can be of radiopaque material.
In a third aspect of the invention, the cable forming the superelastic collagen coated stent can be of linear strands that are arranged in a bundle and fastened or bound at intervals, or continuously, in order to maintain contact among the strands as the cable is bent. One or more of the strands may be radiopaque. This construction is adaptable to guidewires and other structures that must be pushable and/or torqueable, but still remain highly flexible and include radiopacity. Variations on this embodiment can include an outer sheath which consists of a solid or helically wound cover to provide enhanced torqueability and pushability. More specifically, the outer sheath can vary in thickness, stiffness of material or spring of the sheath members to provide desired variations in bending or stiffness of the cable. Such a construction is particularly adaptable to guidewires and the like, and can be varied in terms of the binding or outer layer to alter the torqueability of the cable, and the flexibility of the cable can be varied along its length by the number and sizes of the stranded members in the cable.
In a fourth aspect of the invention, one or more of the strands of the superelastic collagen coated stent can be of a therapeutic material used to enhance treatment of the site after placement of the device. In one presently preferred embodiment of the invention, the cable includes twisted strands of wire around the periphery of the cable, at least one of which is radiopaque. The core of the cable contains a therapeutic agent such as human growth hormone, genetic material, antigens or the like that are intended to become active after placement. Such a construction can be adapted to a variety of interventional therapeutic treatments. In one aspect of this embodiment, one of the strands can have multiple functions, such as providing both a therapeutic effect and also contributing to the structural integrity of the cable. By using copper in such a micro-cable, for instance, the copper can enhance the use of a device made from the cable as on intra-uterine device, with the copper also contributing to the radiopacity and structural integrity of the micro-cable. In the event that such an effect is desired, the therapeutic strand can be placed on the exterior of the cable to enhance contact with the site to be treated.


A re-configurable circuit acts as an Analog-to-Digital Converter (ADC) and as a digital-to-analog converter (DAC). An array of binary-weighted capacitors stores an analog input. Switches connect different capacitors in the array to fixed voltages that cause charge-sharing with a terminal capacitor. The voltage of the terminal capacitor is compared by a re-configurable comparator stage for each different combination of the capacitors. The comparison results are analyzed to determine the closest digital value for the analog input. In DAC mode, the array capacitors are switched based on an input digital value. The switched capacitors connect to a charge-sharing line to generate an analog voltage that is applied to the re-configurable comparator stage. A differential amplifier generates a buffered analog voltage that is fed back to the other input of the re-configurable comparator stage for unity gain. The gain of the re-configurable comparator stage adjusts for ADC and DAC modes.

Larger system chips such as a System-on-a-Chip (SoC) often include analog as well as digital circuits. Signals may cross from the digital domain to the analog domain, and vice-versa. Analog signals may be converted to digital for complex processing, such as by a Digital Signal Processor (DSP), and results may be converted from digital to analog. Some system chips may be configurable to fit several applications, and these applications may have different requirements for analog-digital conversions. However, it is desirable to use the same analog-digital converter circuits for these varied applications.
Many types of Analog-to-Digital Converters (ADC's) have been used for a wide variety of applications. Flash ADC's compare analog signal voltages to multiple voltage levels in an instant to produce a multi-bit digital word that represents the analog voltage. Successive-approximation ADC's use a series of stages to convert an analog voltage to digital bits. Each stage compares an analog voltage to a reference voltage, producing one digital bit. In sub-ranging ADC's, each stage compares an analog voltage to several voltage levels, so that each stage produces several bits. Succeeding stages generate lower-significant digital bits than do earlier stages in the pipeline.
Algorithmic, re-circulating, or recycling ADC's use a loop to convert an analog voltage. The analog voltage is sampled and compared to produce a most-significant digital bit. Then the digital bit is converted back to analog and subtracted from the analog voltage to produce a residue voltage. The residue voltage is then multiplied by two and looped back to the comparator to generate the next digital bit. Thus the digital bits are generated over multiple cycles in the same comparator stage.
FIG. 1 shows a Successive-Approximation-Register ADC. Successive-Approximation-Register SAR 302 receives a clock CLK and contains a register value that is changed to gradually zero-in on a close approximation of the analog input voltage VIN. For example, the value in SAR 302 may first be 0.5, then 0.25, then 0.375, then 0.312, then 0.281, then 0.296, then 0.304, then 0.308, then 0.31, then 0.311, and finally 0.312 when comparing to a VIN of 0.312 volts. SAR 302 outputs the current register value to digital-to-analog converter (DAC) 300, which receives a reference voltage VREF and converts the register value to an analog voltage VA.
The input analog voltage VIN is applied to sample-and-hold circuit 304, which samples and holds the value of VIN. For example, a capacitor can be charged by VIN and then the capacitor isolated from VIN to hold the analog voltage. The sampled input voltage from sample-and-hold circuit 304 is applied to the inverting input of comparator 306. The converted analog voltage VA is applied to the non-inverting input of comparator 306.
Comparator 306 compares the converted analog voltage VA to the sampled input voltage and generates a high output when the converted analog voltage VA is above the sampled VIN, and the register value in SAR 302 is too high. The register value in SAR 302 can then be reduced.
When the converted analog voltage VA is below the sampled input voltage, comparator 306 generates a low output to SAR 302. The register value in SAR 302 is too low. The register value in SAR 302 can then be increased for the next cycle.
The register value from SAR 302 is a binary value of N bits, with D(N−1) being the most-significant-bit (MSB) and D0 being the least-significant-bit (LSB). SAR 302 can first set the MSB D(N−1), then compare the converted analog voltage VA to the input voltage VIN, then adjust the MSB and/or set the next MSB D(N−2) based on the comparison. The set and compare cycle repeats until after N cycles the LSB is set. After the last cycle, the end-of-cycle EOC signal is activated to signal completion. A state machine or other controller can be used with or included inside SAR 302 to control sequencing.
Since ADC's may be relatively large circuits, it is desirable to use ADC's for many applications. It is also desired to use some of the ADC circuits for conversion in the reverse direction, as a DAC. A dual-use circuit that can be used for both an ADC and a DAC is desirable. Circuit components that can be used for both an ADC and a DAC are desirable. A comparator stage that can be configured for use in an ADC and re-configured for use in a DAC is desirable.

Dual-use comparator/op amp for use as both a successive-approximation ADC and DAC

Hong Kong Applied Science and Technology Research Institute Co., Ltd.


A system for thread local garbage collection in a virtual machine environment, comprising: a virtual machine for executing a software application; a memory space for use by the virtual machine in storing software objects and pointers as part of the software application, divided into a global heap and several thread local heaps; a heap maintaining logic that keeps the global heap and the thread local heaps in a state suitable for efficient garbage collecting; and a garbage collector that can collect the thread local heaps in parallel with only the stop-the-world pauses for the global heap.

Virtual machines are abstract computers for which application software can be compiled. The virtual machine is thus an abstraction level for application software that is consistent between different hardware and operating system combinations. Most of the complexity in running the same application on different platforms is handled by the virtual machine and therefore the virtual machine becomes a very complex piece of software. Modern virtual machines need to manage code generation for the particular processor, operating system dependent resources like threads, networking and the file system. The virtual machine also manages the heap, within which allocation and freeing of virtual machine objects is performed. Examples of such virtual machines include the Java Virtual Machine (JVM) and implementations thereof, including the JRockit JVM from BEA Systems Inc., and the Hotspot JVM from Sun Microsystems, Inc.
The definition of the Java Virtual Machine (JVM) does not specify any requirements on the performance or the behaviour of the garbage collection process apart from basic assumptions such as: unused memory should be reused for new objects, and finalizers should be called when objects are to be released. The exact details are explained in the book "The Java™ Virtual Machine Specification (2nd Edition)" by Tim Lindholm published by Sun, and incorporated herein by reference. The JVM implementor can therefore choose to optimize different kinds of behaviours depending on the requirements of the application software and the features of the particular hardware used. A perfect garbage collector would be undetectable to the application software and the software user, there would be no pauses, no extra CPU or memory consumption. Unfortunately no such garbage collector exists and a lot of work has been invested into achieving high performance object allocation and garbage collection with different algorithms for different goals.
Two of the more important problems to solve within garbage collection is to lower the pause times and to increase pause predictability. Pause times include both stop-the-world times where all threads are stopped simultaneously while the garbage collector performs some work, and pause times for each thread separately. Stop-the-world pauses are more disruptive to application software than separate thread pauses. However the sum of all pauses must be limited to allow the application to perform efficiently. For many applications pause predictability is more important than efficiency. Efficiency, to a certain limit can be achieved by purchasing more powerful hardware, but predictable pause times cannot simply be achieved by providing faster hardware.
Object allocation is the companion problem to garbage collection. To avoid locking bottlenecks the standard solution is to give each thread its own thread local area (TLA) on the heap where allocation is performed by pointer bumping. When the TLA is used up, a global free list lock is needed to secure a new TLA for the thread. Since a TLA is simply an area on the heap where only a single thread is allowed to allocate, the objects allocated are immediately eligible for garbage collection if necessary.
Since stop-the-world pauses are undesirable, much work has been spent on ways of splitting the garbage collector work into manageable units, where each unit of work incurs a short pause time, especially that work which requires a stop-the-world pause. Examples of such solutions are concurrent garbage collectors, generational garbage collectors and thread local garbage collectors.
The concurrent garbage collector performs as much as possible of the garbage collecting process in parallel with the software application. To do this the JVM needs to trap all updates to pointers while the garbage collector is running. This is called a "write barrier", and costs cpu-time. The concurrent garbage collector is therefore used when short pause times are more important than efficiency.
The generational garbage collectors allocate objects within a nursery heap. Objects surviving the nursery collection are assumed to be long-lived objects and therefore moved to the old space on the heap which is collected more seldom. The increase in efficiency is based on the assumption that objects die young and it is faster for the garbage collector to collect the small nursery heap to avoid a full collect of the larger old space heap. The generational garbage collector also needs write barriers.
The thread local garbage collector splits the heap into one large global heap and one small local heap for each thread in such a way that each thread local heap can be garbage collected separately from the other thread local heaps. Thread local heaps can potentially increase efficiency both by avoiding collecting the global heap and by lowering the pause times for each thread and to reduce the number of stop-the-world pauses. U.S. Pat. No. 6,912,553 (Kolodner, et al.) teaches a thread local heap collector that traps each update to object pointers in such a way that any object that can be accessed by a thread different from the given thread, will be moved to the global heap. The traps are implemented as software write barriers generated for JVM byte code instructions putfield, putstatic and aastore. Unfortunately, in current thread local heap implementations the gain in garbage collector performance is lost due to the write barriers needed and to the cost of moving objects from the local heap to the global heap.

System and method for optimistic creation of thread local objects in a virtual machine environment


The present invention is an apparatus for simulating corrosion activity in liquid and vapor/condensate corrosion environments. The apparatus includes a container, including a lower region containing the liquid and an upper region, including a condenser, a heater for providing heat to the lower region such that the liquid is maintained at a given temperature, a vacuum pump for providing a partial vacuum at a given pressure in the upper region of the container, one corrosion probe removably positioned in the liquid, and a second corrosion probe removably positioned above the liquid.

The present invention relates to an apparatus for determining corrosion activity in a liquid and vapor/condensate corrosion environment. In particular, the corrosive environment is the interior of an oil refinery apparatus such as a pipestill.
Two leading causes of crude oil corrosion on metal surfaces in refinery pipestills are reactive sulfur compounds and naphthenic acids exposed to pipestill (400–800° F.) temperatures. Corrosion mitigation is practiced by dilution with non-corrosive crudes, installation of corrosion-resistant metallurgy, or addition of chemical corrosion inhibitors, either alone or in combination. Reactive sulfur corrosion e.g. from hydrogen sulfide, is recognized as occurring in either the liquid or vapor phase. On the other hand, naphthenic acid corrosion occurs in liquid and in condensate phases, is enhanced in high velocity regions, but is not believed to be a vapor phase phenomenon.
Commercial inhibitors are typically high boiling and, therefore, concentrate in the bulk liquid phase to minimize the risk of distillate contamination. However, multiple injection ports are frequently necessary to ensure that condensation zones in pipestills are contacted by these agents. This adds to the complexity and cost of inhibitor treatment while increasing the risk of contamination to the petroleum distillate streams. The ability to select a chemical agent that can provide metal protection in multi-phase regions with a single injection would make for a more effective treatment while overcoming the cost and potential product quality issues resulting from inhibitor applications at multiple locations.
Efforts to predict pipestill corrosion have primarily been based on corrosion test results, typically carried out in autoclaves. This can provide a measure of metal coupon corrosion in contact with a bulk liquid phase. However, a coupon placed above the liquid is in a fairly static vapor-liquid environment under pressure from enclosed autoclave. This is totally unlike the dynamic vapor-liquid conditions in pipestills, especially under vacuum in vacuum pipestills. Thus, autoclave corrosion tests are not reliable indicators of condensate phase corrosion and therefore inhibitor performance in that phase cannot be properly evaluated.
As a consequence, refineries using corrosion inhibitors monitor the impact on pipestills by insertion of invariably unreliable corrosion probes and by frequent inspections for evidence of corrosion. When the latter is suspected and/or detected, the refiner typically has three options. One is to add more corrosion inhibitor injection points at indicated locations; another is to alloy up those regions, and the third is to lower the crude feed total acid number (TAN) levels. TAN is typically measured by ASTM method D-664 and is expressed in units of milligrams KOH/gram of oil. Oils with TAN values below 0.5 are generally regarded as non-corrosive, between 0.5 and 1.0 as moderately corrosive, and corrosive above 1.0.

Process for assessing inhibition of petroleum corrosion

ExxonMobil Research and Engineering Company


The invention provides compositions for delivery of cargo to cells. The invention also provides compositions that bind multiple agents simultaneously. The compositions are useful as therapeutics. Methods of using the compositions are also provided.

Each year over 8 million people die worldwide from cancer or cancer-related illnesses. Cancer results from unchecked cell growth, and the unregulated cells invade other parts of the body, hijack nutritional resources, and impair the function of other tissues. Cancer is an indiscriminate killer: although lifestyle factors, such as smoking and diet, can increase one's risk of getting cancer, many cancers are attributable to a person's genetic makeup or to unknown causes. Nearly two in five people will be diagnosed with cancer at some point in their lives.
One strategy for cancer treatment is to use one or more agents that kill actively proliferating cells. For example, chemotherapeutics, such as doxorubicin and 5-fluorouracil, prevent cell division by blocking DNA replication but do not discriminate between cancerous and non-cancerous cells. Consequently, traditional chemotherapeutics kill cancer cells as well as normal cells in tissues where cell turnover is high, such as in the gastrointestinal tract and bone marrow, where blood cells are regenerated. As a result of this brute force approach, patients typically experience serious side effects.
More recently, cancer therapies have focused on the use of reagents that target molecules, such as proteins, involved in the growth or spread of cancer cells. However, targeted therapies have their own limitations. First, delivery of the reagent to its target within the body can be challenging. In addition, cancer cells can develop resistance to a targeted reagent. For example, the target can mutate, or the cancer cells can adapt to become independent of the pathway in which the target functions. Thus, the ability to deliver potent agents to cancer cells to prevent their growth is limited, and millions of people continue to die from cancer each year.

Compositions for delivery of cargo to cells


The present invention provides an inkjet recording apparatus includes an inkjet head, a conveyor, a printing controller, an image sensor, a blocking object determining unit, and a blocking object dealing unit. The inkjet head has an ejection surface in which plural ejection outlets ejecting ink are formed. The conveyor has a placing member on which a recording medium is placed and conveys the placing member to a position opposing the ejection surface. The printing controller causes the conveyor to convey the placing member to the opposing position and causes the inkjet head to eject the ink towards the opposing position. The image sensor captures an image of at least one of (i) a surface of the recording medium placed on the placing member, (ii) a surface of the placing member, and (iii) the ejection surface. The blocking object determining unit determines, based on the image captured by the image sensor, whether an object which blocks the flight of the ink exists between the ejection outlets and the opposing position so as to obstruct at least two neighboring ejection outlets among the ejection outlets. The blocking object dealing unit carries out a predetermined blocking object dealing operation when the blocking object determining unit determines that the object blocking the flight of the ink obstructs at least two neighboring ejection outlets among the ejection outlets.

1. Field of the Invention
The present invention relates to an inkjet recording apparatus having ejection outlets ejecting ink.
2. Description of Related Art
In an ink inkjet recording apparatus having an inkjet head in which two or more ejection outlets are formed to eject ink therefrom, the ink ejected from the inkjet head to a recording medium may not be properly deposited on the medium. In this regard, a conventional approach is such that a chart for detecting the misfiring of ink is printed by each nozzle, and the chart is read out by a reading unit constituted by a line sensor and the like. Which nozzle is misfiring is determined by analyzing the read data.
Several reasons are conceivable why ink is not properly deposited on a recording medium. For example, ink is not properly ejected from the ejection outlets because there is something wrong in the inkjet head. Another example is that something obstructing the flight of ink adheres to the inkjet head. As such, to solve the problem of improper deposition of ink on a recording medium, it is necessary to take a suitable action corresponding to the cause of the problem. The aforesaid conventional approach, however, does not make it possible to determine what is a proper action, because determined according to the conventional approach is merely whether each nozzle is misfiring or not. For this reason, the conventional approach may not be sufficient to properly solve the problem of improper deposition of ink from the inkjet head to a recording medium.


The invention relates to a method and system for establishing a first type of connection, wherein a handshake processing is performed with the other party of the first type of connection. If the handshake processing is successful, the first type of connection is established. If the handshake processing is not successful, i.e. the other party does not support the first type of connection, a fallback procedure is started to change the call to a second type of connection determined during the connection establishment. The change to the second type of connection may be performed directly or may be based on a call retry procedure. Thereby, inconvenient disconnections or error processings at the end terminals can be prevented.

In recent years, multimedia telephone terminals which can be connected to fixed networks have been developed. These terminals provide real-time video, audio, or data, or any combination thereof, between two multimedia telephone terminals over a voice band network connection. Communication may be either one-way or two-way. A multipoint communication using a separate Multipoint Control Unit (MCU) among more than two terminals is also possible. Furthermore, the multimedia telephone terminals can be integrated into PCs or work stations, or can be stand-alone units.
Interworking with such visual telephone systems on mobile radio networks is defined in the ITU-T video/multimedia recommendation H.324/M.
However, in general, a calling party does not know in advance whether or not the terminal of a called party supports the connection type underlying a desired call. Thus, inconvenient error processings and disconnections may occur, if the terminal of the called party does not support the desired connection type, e.g. the multimedia connection.

Method and system for establishing a connection in a telecommunication network having different protocols


A variable valve drive for changing control timing of cam-actuated gas-exchange valves of an internal combustion engine is provided, with a tappet (6a, 6b, 6c), which, with convex cam engaging contour (5), engages a cam (4a, 4b, 4c) of a camshaft (3a, 3b, 3c) and which is guided so that it can move in the longitudinal direction in a rotatable tappet guide (7a, 7b, 7c), whose rotational angle (9) is adjustable for changing the control timing. In this way, the tappet guide (7a, 7b, 7c) can rotate about a rotational axis (8) parallel to a longitudinal axis (2) of the camshaft (3a, 3b, 3c).

A valve drive of this type is known from the U.S. Pat. No. 6,155,216, which is considered to be class forming. In this document, the control timing are not changed as usual through angular adjustment of the camshaft relative to the crankshaft by means of a camshaft adjuster, but instead through changes to the contact point angle of camshaft engaging contour of a tappet relative to a cam of the camshaft.
For this purpose, the cited document proposes a tappet guide that can rotate in the internal combustion engine and that can have its rotational angle adjusted within an eccentric opening to allow the tappet to move supported in the longitudinal direction. When the tappet guide rotates about its longitudinal axis, the tappet moves on a circular track, whose radius—viewed in a projection in the tappet longitudinal direction—corresponds to the eccentricity of the opening. Because the cam engaging contours of the tappet also have a radius, the track profile of the contact point between the cam and cam engaging contours simultaneously describe a circular arc—viewed in a projection in the longitudinal axis of the camshaft. Because the track profile represents the sum of the possible contact points between the tappet and cam, the angle enclosed by the circular arc corresponds to a camshaft-related change to the control timing of the gas-exchange valve actuated by this tappet.
Consequently, this principle can be used very advantageously for a cam-selective change of the control timing of gas-exchange valves. This relates especially to internal combustion engines with only a single camshaft, on which the cams are arranged together for actuating inlet valves and outlet valves. This is because, in the cases, in which the control timing of only inlet valves or only outlet valves or inlet valves and outlet valves are to be changed independently from each other, just the use of a conventional camshaft adjuster can not support this objective.
Nevertheless, the geometrical conversion of this principle proposed in the cited document has a few serious disadvantages. First, the eccentricity of the tappet in the tappet guide increases with the maximum change of the control timing to be achieved, so that the track profile of the contact point also extending in the longitudinal direction of the camshaft leads to a considerable increase in the necessary cam width. However, the cam width is restricted to tight limits in modern and compact valve drives and especially in multi-valve per cylinder internal combustion engines, so that the proposed methods can utilize only a small portion of the geometrically possible potential for changing the control timing due to the limited eccentricity of the tappet guide. Second, the tappet frequently has a cam roller as low-friction cam engaging contours to the cam. For this reason, the tappet is to be protected from twisting about its longitudinal axis and requires a highly complex torsion lock construction due to the track curve described by it. This torsion lock follows the track curve while limiting the rotational degree of freedom of the tappet. As an example for the effort to be expended in the conversion of a torsion lock suitable for this purpose, is noted in US 2004/0065282 A1.

Variable valve drive for changing the control timing of cam-actuated gas-exchange valves


A method for severing integrated-circuit conductive links by laser power employs a phase plate (26) to shape the laser beam's intensity profile. The profile thus imparted to the beam approximates the Fourier transform of the intensity profile desired on the workpiece (34). As a consequence, when a focusing lens (32) receives a beam having the profile imparted by the phase plate (26), it focuses that beam into a spot on the workpiece (34) having an intensity profile more desirable than the ordinary Gaussian laser-beam profile.

The present invention is directed to the use of laser light in integrated-circuit fabrication. It is directed particularly to severing conductive links in otherwise completed electronic circuits so as to indicate which parts of the circuit are defective and cannot be used and which spare parts of the circuit are to be used in their stead.
The designs of some large semiconductor-memory chips take into account the fact that the high number of memory cells makes a fabrication defect likely. To reduce the resultant waste, these designs include extra cells in the form of spare rows and columns that can be brought into use if a standard row or column is found to be defective. If testing reveals that a row or column is defective, the manufacturer vaporizes certain conductive links in the chip, thereby removing the defective row or column from service and programming the chip to replace the removed row or column with one of the spares.
The chip 10 of FIG. 1 shows in simplified form a possible arrangement of one of the conductive links used for encoding. Formed on a thick substrate 12 of single-crystal silicon might be a thin layer 14 of silicon dioxide. A conductive link 16 made, for instance, of a tungsten or molybdenum layer 18 bonded by sintering to a polysilicon layer 20 may be disposed between layer 14 and one or more oxide layers 22.
To break the link 16, a laser beam is focused through the layers 22, which are essentially transparent to the laser-beam wavelength employed, and onto the link, which absorbs the laser-beam energy and vaporizes, rupturing the layers above it to allow the erstwhile link material to escape.
Successful application of this technique depends greatly on various process parameters as well as on the particular chip design. Excessively intense laser radiation at isolated locations, for example, can result in damage to surrounding material, such as the thin oxide layer 14, and could thus result in operational defects. On the other hand, insufficient beam intensity or duration tends to permit flashing that causes undesirable remaining continuity in the link.
For this reason, considerable effort has been directed to so adjusting various process variables as to sever links reliably. One such process variable is the beam's intensity profile. Ordinarily, the intensity profile of a laser beam is Gaussian as a function of distance from the center of the beam. This profile is not optimum for link severing, however, because a significant length of the link needs to be vaporized; if the skirt regions of the Gaussian curve are to be counted on to provide the necessary vaporization energy, the center, peak region of the beam may deliver excess power at a localized region in the link and thus cause damage to the chip. This effect is exacerbated by the nonlinear nature of the heating process: the hotter the link material becomes, the more efficient it is at absorbing energy from the beam. On the other hand, if only the central, maximum region is counted on to deliver the requisite vaporizing intensity, then the beam has to be widened to such an extent that the total laser power required for a given intensity is undesirably high.
For these reasons, efforts have been made to make beam intensity more uniform. In one link-vaporizing arrangement, for instance, the beam is directed to an aperture through which only the central part of the beam can pass. To some extent, this approach does contribute to intensity uniformity. But it suffers from the inefficiency that arises from the fact that the power in the outer parts of the Gaussian curve is wasted. Moreover, I have found that such an approach tends to result in "hot spots" that result from diffraction that the aperture causes.

Method for severing integrated-circuit connection paths by a phase-plate-adjusted laser beam


A method of verifying the integrity of a virtual machine in a cloud computing deployment comprises: creating a virtual machine image derived from a trusted virtual machine, wherein the trusted virtual machine has a Keyless Signature Infrastructure signature stored in a signature store; and verifying that a computation resource can be trusted. If it is verified that a computation resource can be trusted, the method further comprises: submitting the virtual machine image to the trusted computation resource; checking a signature of the virtual machine image against the stored signature of the trusted virtual machine; launching the virtual machine image on the trusted computation resource, and creating a Keyless Signature Infrastructure signature of the virtual machine image; and storing the signature of the virtual machine image in a signature store.

It is desirable to deploy virtual machines in a cloud computing deployment. In such a system, the virtual machine acts as a software emulation of a specific computer system running specific software. The virtual machine can then execute on computation resources that are provided in the cloud.
It is preferable that virtual machine images that are launched by a tenant are based on a trusted source, and that the integrity of the images can be attested over their whole lifecycle. In addition the tenant will typically prefer that the virtual machine should execute only on compute resources that are trustworthy, for example on resources that have been booted or created with approved software components.
Here we use the word "launch" to mean the start of code execution of, say, a virtual machine image by a compute resource that is in operation. The word "boot" means to start code execution of, say the code of the compute resource, by a compute resource, usually hardware, that is in a pristine state.
Solutions that are based on a Public Key infrastructure, such as described in US2011/0302415 or US2015/0134965, require trust establishment with a trusted third party. In any event, such solutions are problematic in large scale implementations, because of the complexity of issues related to certificate lifetime and certificate management, such as certificate renewal, certificate revocation and certificate long-term storage.


Transient voltages are not propagated through a P-channel MOSFET used as a switch with output slew rate control feedback, by connecting a low or near-zero impedance across the source and gate terminals of the device whenever the MOSFET is supposed to be off. The low or near-zero impedance is provided by a second P-channel MOSFET connected across the source and gate of the MOSFET switch.

In an automotive electrical system, it is often critically important that devices directly connected to the vehicle battery limit the current they consume during low power scenarios, such as when vehicle ignition is off. This is to prevent unnecessary discharge of the vehicle battery while the engine is not running. In order to achieve this goal in an automotive electronic device, it is common practice to place one or more power switches in series between the battery input of the power system and the power inputs of downstream circuitry in order to allow them to be fully powered off during low power scenarios.
The power supply line for integrated circuits and downstream loads is typically decoupled with a several distributed capacitances to ground. That distributed capacitance, along with any other lumped parallel capacitance, is electrically equivalent to a short circuit during the occurrence of high frequency voltage transients on the power supply line, such as the fast turn-on transition caused by an upstream power switch. Uncontrolled inrush current into distributed capacitance can cause damage to the power switch, upstream components or the capacitors themselves, and can also potentially blow an upstream fuse.
When using a voltage-controlled semiconductor-based switch, whose output is controlled based on the difference between its control node and its input (such as a P-channel MOSFET), it is a common practice to introduce capacitive feedback from the output of the switch to the control node of the switch so that the slew rate of the voltage ramp that it applies to the downstream distributed capacitance during its turn-on transition is precisely controlled, thereby limiting the inrush current that is conducted into the downstream distributed capacitance while providing a predictable turn-on time. For the "off" state, a resistance is typically connected between the gate and the source of the MOSFET. An unfortunate consequence of using such a slew-rate controlling capacitance connected from output to control node of a semiconductor switch, along with a resistor to effectuate the "off" state, is that the off-state resistor and slew-rate controlling capacitance can create a mechanism that enables or turns on the semiconductor switch if an upstream voltage transient occurs by introducing a transient difference between the input and the control node. Thus the switch with output-connected capacitive slew-rate control feedback may not always fulfill its duty of blocking downstream current when it is expected to be disabled.
An apparatus and method for effectively suppressing the propagation or transmission of voltage transients through a semiconductor switch having a slew rate that is controlled using output-connected capacitive feedback, when the switch is expected to be disabled, would be an improvement over the prior art.

Preventing voltage pulse propagation in a disabled capacitive feedback slew-controlled switch


A method of forming a capacitor structure includes the steps of forming a conductive layer on a microelectronic substrate, and forming a first hemispherical grained silicon layer on the conductive layer opposite the substrate. A protective layer is formed on the hemispherical grained silicon layer. The protective layer, the first hemispherical grained silicon layer, and the conductive layer are then patterned so that portions of the microelectronic substrate are exposed adjacent the patterned conductive layer. A second hemispherical grained silicon layer is formed on the surface of the protective layer opposite the first hemispherical grained silicon layer, on sidewalls of the patterned conductive layer, and on the exposed portions of the microelectronic substrate. Portions of the second hemispherical grained silicon layer are removed from the exposed portions of the microelectronic substrate, and the patterned protective layer is then removed.

As dynamic random access memory (DRAM) devices become more highly integrated, the area of the substrate available for each memory cell is reduced. A predetermined memory cell capacitance, however, should be maintained despite the reduced substrate area available to maintain a memory cell's reading capacity, reduce soft errors, and facilitate low voltage operation. Accordingly, there is a need to provide memory cell capacitors having a predetermined capacitance on a smaller surface area of a microelectronic substrate.
Techniques have been discussed to provide capacitor electrodes having increased surface areas on smaller portions of a microelectronic substrate. In particular, the surface area of a capacitor electrode can be increased by forming a hemispherical grained silicon (HSG-Si) layer on the electrode surface. For example, HSG silicon layers have been formed using native oxide film removal and high vacuum annealing techniques as discussed in the reference by H. Watanabe et al. entitled "An Advanced Fabrication Technology of Hemispherical Grained (HSG) Poly-Si for High Capacitance Storage Electrodes", SSDM, pp. 478-480,1991.
According to known HSG-Si fabrication techniques, however, the formation of the HSG-Si layer may result in undesired conductive paths between storage electrodes. In addition, the resulting HSG-Si layer may be insufficiently doped thus making it difficult to obtain a desired conductivity. Accordingly, it may be necessary to remove portions of the HSG-Si layer between storage electrodes. In particular, an etch-back step can be used to remove portions of the HSG-Si layer between the storage electrodes. The etch-back step, however, may damage portions of the HSG-Si layer on the storage electrodes and reduce a surface area thereof.
The dopant concentration of the HSG-Si layer can also affect the reliability of the resulting capacitor. In particular, an HSG-Si layer with an insufficient conductivity may result in an undesired variation in the C-V characteristics of the capacitor by lowering the ratio of Cmin to Cmax (Cmin/Cmax). For example, the capacitance may be at a minimum (Cmin) when a positive voltage is applied to a storage electrode with an insufficient concentration of an N-type dopant, and at a maximum (Cmax) when a negative voltage is applied to the storage electrode. Accordingly, the ratio of Cmin to Cmax may be reduced thus reducing the reliability of the capacitor.

Methods of forming hemispherical grained silicon (HSG-Si) capacitor structures including protective layers


A regenerative oxidant preheater internal arrangement, including a system and method for use thereof, utilizing a unique recycle oxy-combustion methodology which includes at least two primary combustion oxidant sectors placed adjacent to both the flue gas side as well as a secondary oxidant sector positioned between the two primary sectors. A tri-sector regenerative oxidant preheater apparatus, method and arrangement for utilization with oxy-fired pulverized coal combustion power plants.

The present invention relates, in general, to the field of oxidant heaters (air heaters and air pre-heaters) for use in coal-fired power plants and in particular to a system and method for use in oxy-fuel combustion which incorporates a novel regenerative oxidant preheater internal sector arrangement as well as the strategic positioning of the primary oxidant fan and primary oxidant mixer. The present invention relates in part to minimizing the loss of oxygen through leakage of oxidant into the gas side of a rotary regenerative oxidant preheater.
Air quality laws, both at the federal and state level have set increasingly stringent emission standards.
Often of particular concern are sulfur dioxide and other acidic gases produced by the combustion of fossil fuels and various industrial operations. Acidic gases are known to be hazardous to the environment, such that their emission into the atmosphere is closely regulated by clean air statutes.
New technologies are addressing this problem so that fossil fuels and particularly coal can be utilized for future generations without polluting the atmosphere and contributing to global warming. One of the technologies being developed has potential for retrofit to existing pulverized coal plants, which are the backbone of power generation in many countries. This technology is oxy-fuel combustion which is the process of firing a fossil-fueled boiler with an oxygen-enriched gas mix instead of air. Almost all the nitrogen is removed from the input air, yielding a stream that is approximately 95 percent oxygen. Firing with pure oxygen would result in too high a flame temperature, so the mixture is diluted by mixing with recycled flue gas. Oxy-fuel combustion produces approximately 75 percent less flue gas than air fueled combustion.
About 70 percent to 80 percent of the flue gas exiting the wet scrubber of an oxy-fired pulverized coal combustion plant is returned to the boiler where oxygen is introduced to produce the combustion oxidant gas, while the remainder of the flue gas is sent to a purification and compression system where it is prepared to suit pipeline and storage requirements. Thus, it is imperative that the carbon dioxide concentration be as high as possible with a low concentration of sulfur, nitrogen, oxygen, and water as can be practically and economically achieved.
Oxy-fired pulverized coal combustion burns pulverized coal in an oxidant comprised of a mixture of relatively pure oxygen and recycled flue gas to reduce the net volume of flue gases generated from the combustion process in a boiler, and to substantially increase the concentration of carbon dioxide in the flue gases. The recycled flue gas represents a portion of the flue gases generated by the combustion process and acts to dilute the flame temperature and maintain the volume necessary to ensure adequate convective heat transfer to all boiler areas, and can also be used to dry and carry the pulverized coal to the combustion space of the boiler.
The oxidant used in oxy-fired pulverized coal combustion is, in one non-limiting instance, heated in rotary regenerative type air preheaters, even though such air preheaters encounter leakage from the air side to the gas side. Tubular and plate type air preheaters do not experience leakage and provide a reasonable alternative to the rotary regenerative air preheater at industrial boiler scale. However, this is not a cost effective alternative at the electric utility boiler scale.
In conventional pulverized coal firing, a small portion of the air required for combustion is used to dry and carry the pulverized coal to the burners for burning the coal in the furnace or combustion space of the boiler. This portion of the air is known as primary air. In direct firing systems, primary air is also used to dry the coal in the pulverizer. The remainder of the combustion air is introduced in a windbox housing the burners, and is known as secondary air.
Rotary regenerative air preheaters are relatively compact and are the most widely used type for combustion air preheating in electric utility boiler plants. Rotary regenerative air preheaters transfer heat indirectly by convection as a heat storage medium is periodically exposed to heat-emitting flue gases and heat-absorbing combustion air. The rotary regenerative air preheater includes a cylindrical shell or housing that contains a coaxial rotor packed with metal heat storing corrugated plates which are bundled so as to present flow passageways therebetween. The preheater is divided into a gas side which is under negative pressure and an air side which is under positive pressure. The most prevalent flow arrangement has the flue gases entering the top of the rotor and the combustion air entering the bottom of the rotor in counter flow fashion. Consequently, the cold air inlet and the cooled gas outlet are at one end of the preheater, usually referred to as the cold end, the hot gas inlet and the heated air outlet are at the opposite end of the preheater, usually referred to as the hot end. As a result, an axial temperature gradient exists from the hot end of the rotor to the cold end of the rotor. In response to this temperature gradient, the rotor tends to distort and to assume a shape similar to that of an inverted dish, commonly referred to as rotor turndown.
In operation, the rotor is rotated slowly about a central shaft, making one to three revolutions per minute causing each bundle of heat absorbing plates to be placed, alternately, into the flow path of the heat-emitting flue gases and the flow path of the heat-absorbing combustion air. The most notable characteristic of rotary regenerative air preheaters is that a small but significant amount of air leaks from the positive pressure air side to the negative pressure gas side due to rotor turndown and the rotary operation of the air preheater. In order to prevent undue leakage from the air side to the gas side, the air preheater is provided with radial, axial and peripheral seals. It is known to construct these seals of thin, flexible metal. The seals are adjusted when the gaps are the largest. This means that, when the gaps are small due to expansion of the rotor and the housing, the seals may be severely bent and forced into high contact pressure with the rotor or housing. For this reason, seals wear relatively quickly and require replacement.
In a prior art or conventional regenerative air or oxidant preheater arrangement, the primary air or oxidant is at a positive pressure of about 40 inches of water gage ("inches wg"), the secondary air or oxidant is at a positive pressure of about 20 inches wg, and the flue gas is at a negative pressure of about 5 inches wg. This conventional air or oxidant preheater has the air or oxidant side of the preheater divided into three sectors, a central sector which receives the primary air or oxidant and is flanked by a pair of sectors which receive the secondary air or oxidant and are located adjacent the flue gas side portion of the preheater. This arrangement minimizes the pressure difference across the seals between the air or oxidant side and the gas side to about 25 inches wg, which results in 7 percent to 14 percent leakage of air or oxidant into the flue gas. These values, though representative of a coal fired plant, may vary depending on fuel and equipment variations and are not intended as absolute.
In an oxy-fired pulverized coal plant the combustion process is carried out by the oxidant, which is comprised of a mixture of relatively pure oxygen and recycled flue gas, with a portion thereof being used to dry and transport the pulverized coal to the burners and the remainder being introduced into the boiler combustion space. The oxidant must be heated before entering the combustion process, and the equipment of choice is a rotary regenerative air preheater since it is cost effective for electric utility power plants. However, the leakage occurring in the regenerative oxidant preheater from the positive pressure oxidant to the negative pressure flue gas represents a loss of oxygen and recycled flue gas to the gas side of the regenerative oxidant preheater. This loss of oxygen along with the recycle gas requires additional oxygen production in an air separation unit to make up for the loss of oxygen, and it also requires the removal of the leaked oxygen from the product gas in a compression and purification unit before the concentrated carbon dioxide can be disposed of via storage or use for enhanced oil recovery, since pipeline line and use constraints require that the flue gas be as high in concentration of carbon dioxide and as low in concentration of nitrogen, sulfur, oxygen and water, as practical. Both of these remedial procedures result in increased plant operating costs. Thus, oxidant introduction into the flue gas must be minimized or eliminated. Furthermore, it is undesirable for an oxidant with a high concentration of oxygen to be exposed to ash potentially containing some combustible carbon and thereby raising the concern of fire.
In one process variation, warm recycle, the flue gas leaving the oxidant preheater is immediately split into two streams. One stream passes through particulate, SO2, and moisture removal as described herein, before being further split between the primary and exit stream to a CPU. The other, secondary stream, passes through particulate removal, and is routed back to the oxidant preheater in a "warm" state (about 400° F.).
Regenerative oxidant heaters transfer heat indirectly by convection as a heat storage medium is periodically rotated into the hotter and cooler flow streams. In steam generating plants, tightly packed bundles of corrugated steel plates serve as the storage medium. In these units either the steel plates, or surface elements, rotate through oxidant (or air) and gas streams, or rotating ducts direct oxidant and gas streams through stationary surface elements.
The conventional regenerative oxidant preheater which is most commonly used is the Ljungstrom® type which features a cylindrical shell plus a rotor which is packed with bundles of heating surface elements which are rotated through counterflowing oxidant and gas streams. FIG. 1 shows the typical positioning of the sectors through which the primary oxidant stream 58 and secondary oxidant stream 34 as well as the counterflowing flue gas stream 98 flows in a conventional Ljungstrom® type regenerative oxidant heater. As is shown, oxidant flows through one half of the rotor and flue gas which comes from the boiler's gas exit flows through the other half. Additionally, the oxidant side (or "air side") consists of two sectors, one for the primary stream and one for the secondary stream.
Another common conventional regenerative oxidant preheater sector arrangement includes that which is disclosed in United States Patent Application Publication No. 2006/0090468. The regenerative oxidant preheater of United States Patent Application Publication No. 2006/0090468 is adapted to receive a flow of cool oxidant in counterflow to the flow of hot flue gas and to provide a heat exchange between the cool oxidant and the hot flue gas to convert the cool oxidant into the heated combustion oxidant. FIG. 2 is a bottom cross sectional view of the rotor of an oxidant preheater with a typical sector arrangement, which is also employed in United States Patent Application Publication No. 2006/0090468. It shows the primary oxidant sector 40, and the secondary oxidant sector 42, through which respective primary and secondary oxidant streams flow toward a boiler. The primary and secondary sectors 40 and 42, respectively, are separated by a sector plate 44 and they are both adjacent to flue gas sector 38, through which flue gas flows away from a boiler. Additionally, the primary and secondary sectors 40 and 42 are separated from the flue gas sector 38 by sector plates 46 and 48.
In conventional regenerative oxidant heaters for an air-fired power plant, a typical pressure for the primary oxidant stream is high as compared with that of both the secondary air stream and the flue gas stream. For example, a typical pressure for the primary oxidant stream is about +40 inches wg, for the secondary oxidant stream it is about +20 inches wg, and for the flue gas stream from the boiler it is about −5 inches wg. Thus, between the secondary air sector and gas side there is about a +25 inches water gauge difference in air pressure which can result in 14 percent leakage of the oxidant into the gas side. Furthermore, the pressure gradient between the primary air sector and the gas side is much greater.
In all regenerative heaters which use conventional sector arrangements such as those discussed above, the rotating heat exchanger in combination with the pressure differential between the respective streams causes inherent leakage between the air (or oxidant) side and the gas side conveying the hot flue gas from the boiler.
However, in oxy-fuel combustion, all these configurations result in leakage from the oxidant to the gas side. In addition most of the oxygen must be added to the recycled flue gas upstream of the oxygen preheater in order to achieve a reasonable flue gas temperature leaving the oxidant heater. Thus any leakage results in the loss of costly oxygen along with recycle gas to the exit stream thereby necessitating additional oxygen production in an air separation unit (ASU) to make up for the loss as well as removal of additional oxygen from the product gas in a compression and purification unit (CPU) before the concentrated CO2 can be disposed of. A need exists to minimize such leakage as the cost of additional oxygen production and removal is prohibitive.
An additional problem encountered when using an oxidant preheater employing a conventional sector arrangement in oxy-fuel combustion, is difficulty achieving acceptable exit gas temperature. Due to the high temperatures of the flue gas and oxidant streams, it can be very difficult, especially evident in warm recycle, to achieve an acceptable gas temperature at the oxidant preheater exit.
Furthermore, the concern about costly oxygen loss as well as the problem caused by the high temperature of the oxidant(s) and flue gas makes it difficult to achieve a design that balances both acceptable heat exchanges within the oxidant preheater as well as reasonable oxidant preheater exit gas temperatures.
When attempting to achieve such a balance, a typical known step is to add cool oxidant to the oxidant flow stream(s) prior to (i.e., upstream from) the oxidant heater. However, this conventional method is undesirable because leakage from the oxygenated oxidant stream(s) into the boiler flue gas stream results in the loss of costly oxygen. The loss of oxygen occurs because a substantial portion of it will flow in the stream which leads to the compression process. Additionally, if the oxygen is added to the primary or secondary oxidant stream after the oxidant preheater an acceptable oxidant preheater design becomes more difficult to achieve.
Another common approach which has been taken in an attempt to reduce leakage and hence loss of costly oxygen, is to locate the primary oxidant fan downstream of the oxidant heater. However, this approach has consistently been ineffective.
Additionally, a known alternative to using a regenerative oxidant preheater in order to eliminate internal leakage and avoid loss of costly oxygen, is to use expensive separate primary and secondary tubular or plate type preheaters for the secondary and primary oxidant streams which completely separates the oxidant side and the gas side allowing no leakage. However, although this alternative may be reasonable for use on the industrial boiler scale in air fired applications, it is not cost effective when applied to large utility boilers. Additionally, separate tubular preheaters require considerably more space than regenerative oxidant heaters and tubular preheaters are susceptible to significant internal leakage with age, thus inevitably resulting in oxidant loss.
Accordingly there is a clear need for a cost effective system and method which incorporates a regenerative oxidant preheater design that will minimizes the loss of costly oxygen normally caused by internal oxidant preheater leakage and which will also achieve an acceptable balance between reasonable heat exchange within the oxidant preheater and a reasonable oxidant preheater exit flue gas temperature.

Oxy-fuel combustion oxidant heater internal arrangement


The present invention comprises a new and distinct cultivar of Chrysanthemum, botanically known as Dendranthema grandiflora, and referred to by the cultivar name Golden State Daisy is described. The plant is particularly characterized by its golden yellow color and elliptic/spoon shape of its ray florets.

Golden State Daisy was found as a natural daisy from mutation (sport) of the variety Golden State (U.S. Plant Pat. No. 8,694) by Jose Luis Cardona in a controlled environment at Clearwater Nursery, Nipomo, Calif. 93444, U.S.A. This mutation was discovered as one flowering shoot within a flowering bench of seedlings of Golden State, in April of 1993.
The first act of asexual reproduction of Golden State Daisy was accomplished when Jose Luis Cardona took vegetative cuttings in July of 1993, in a controlled environment in Nipomo, Calif.
Horticultural examination of controlled flowerings of successive plantings has shown that the unique combination of characteristics as herein disclosed for Golden State Daisy are firmly fixed and are retained through successive generations of asexual reproduction.
Golden State Daisy has not been observed under all possible environmental conditions. The phenotype may vary significantly with variations in the environment such as temperature, light intensity and day length.
The following observations, measurements and comparisons describe plants grown in a controlled environment in Nipomo, Calif. Unrooted cuttings were directly stuck into 6.4" pots and grown under the natural temperature and day length prevailing in June through August of 1997.
The following traits have been repeatedly observed and are determined to be basic characteristics of Golden State Daisy, which in combination distinguish this Chrysanthemum as a new and distinct cultivar.
1. Flat capitulum form.
2. Flat capilulum type.
3. Yellow fully expanded ray florets.
4. Yellow Daisy disc with green eye.
5. Diameter across the face of the capitulum is 8.5 cm.
6. Exceptional uprignt to spreading habit when an average of 5 breaks after a single pinch.
7. Flowering response is approximately 59 days from the start of short days.
8. Relatively easy to control plant height from bench such that the finished height will range from 16 inches to 18 18 inches depending on pot size and market requirements.
Golden State Daisy differs from its parent, Golden State (U.S. Plant Pat. No. 8,694), in the following ways.
1. The flower in Golden State Daisy has a traditional daisy eye; i.e., the disc florets do not dramatically increase in length as the disc matures. In contrast, the eye of the Golden State flower is that of a true anemone, having disc florets that significantly increase in length as the flower matures.
Golden State Daisy differs from Golden State's parents Indo (U.S. Plant Pat. No. 6,774) and Hopscotch (U.S. Plant Pat. No. 5,816) in the following ways.
1. Golden State Daisy has an 8.5 week response time, while Indo and Hopscotch have an 8 week response time.
2. Indio is an anemone rather than a daisy and is shorter than Golden State Daisy
3. There are no known foliage sensitivities with Golden State Daisy (nor Golden State while Indio has known sensitivity to the chemical pesticide. Dursban.
4. Hopscotch is not recommended for year round production, while this not not a problem for Golden State Daisy.

Chrysanthemum plant names `Golden State Daisy`


The present disclosure provides a portable electronic device having a sensor arrangement for gesture recognition and a method for gesture recognition. In accordance with one example embodiment, the portable electronic device comprises: a processor; a flexible housing including a magnet; a magnetic sensor connected to the processor which monitors a magnetic field generated by the magnet.

Electronic devices, including portable electronic devices, are increasingly being configured for gestural control as part of the movement towards ubiquitous computing in which devices are adapted for more natural and intuitive user interaction instead of requiring the user to adapt to the device. The majority of gestural controls are in the form of touch gestures detected with a touch-sensitive display or motion gestures detected with a motion sensor such as an accelerometer. Alternative forms of gestural control are desirable to provide a more natural and intuitive user interaction with an electronic device.

Portable electronic device having a sensor arrangement for gesture recognition


Power couplings are provided from outside the shell of a superconducting magnet through the intervening space and through the cryogen pressure vessel to the magnet coils within the vessel. The multi-pin shim magnet connector is replaceable without cutting the vessel open and the shim and main magnet main coil connectors include central apertures through which cryogen boil-off gas is flowed before venting to cool the connectors and reduce boil-off.

This invention relates to improved power connectors for superconducting magnets which connect external power through the pressurized magnet vessel to the coils inside the vessel.
As is well known, a magnet can be made superconductive by placing it in an extremely cold environment, such as by enclosing it in a cryostat or pressure vessel containing liquid helium or other cryogen which slowly boils off, forming a cryogen gas which is vented out of the cryostat. The extreme cold reduces the resistance in the magnet coils to negligible levels, such that when a power source is initially connected to the coil (for a period, for example, of only ten minutes) to introduce a current flow through the coils, the current will continue to flow through the coils due to the negligible resistance at superconducting temperature even after power is removed, thereby maintaining a magnetic field. Superconducting magnets find wide application, for example, in the field of magnetic resonance imaging (hereinafter "MRI").
In a typical superconducting magnet, the cryostat or pressurized helium vessel is positioned within, but spaced from, a vacuum vessel with a significant temperature gradient therebetween. As a result, the shim lead connector assembly and power leads must extend through a wide temperature range from the outside of the vacuum vessel to the interior of the pressurized vessel.
A multi-pin cryostat connector typically extends through the wall of the cryostat for coupling to the plurality of shim or adjusting magnets, commonly with male pins on the exterior and extending away from the cryostat, to enable coupling through a mating female connector. The cryostat connector can be damaged by multiple insertion and retraction operations of the shim lead coupling assembly, particularly since the connectors must be mated by manipulation of the shim lead connector assembly from a distance, typically well in excess of one foot, from the outside of the vacuum vessel.
A power coupling assembly for which the present invention is applicable is disclosed in co-pending U.S. patent application, Ser. No. 07/880,848 filed May 11, 1992 by William S. Stogner and Daniel C. Woods, assigned to the same assignee as the present invention, and hereby incorporated by reference. In such an arrangement, if the connector pins of the cryostat connector are damaged, it is a difficult and costly procedure to replace the cryostat connector since it passes through the pressurized vessel and vacuum vessel. As a result, the pressurized vessel and the vacuum vessel must be cut open, the cryostat connector replaced, and the pressurized vessel and vacuum vessel subsequently reassembled and vacuum space evacuated.
Similarly, a main coil power connection is provided through the pressurized vessel to carry the heavy currents used to energize the main coils. The current to the main magnet coils is far larger than that to the shim magnet coils, such that it is also important to minimize the resistance heating due to that current flow.
However, any solution to these problems must avoid increasing the resistance heating resulting from current flow through the connector assembly, since even a single watt of heating can result in the boiling of 1.4 liters per hour of helium, which is completely unacceptable, since a typical MRI specification limits the helium boil-off to only 0.2 liters per hour. Accordingly, it is important to reduce and minimize the resistance heating resulting from current flow through the MRI power connectors to the superconducting magnets. Also, any solution must insure positive electrical contact, and be practical and useful in the presence of conflicting thermal, electrical and mechanical considerations.

Connector cooling and protection for power coupling assembly for superconducting magnets