A method for improved detection and imaging of ultrasound contrast agents using dual-band transmitted pulses, is described. The method is based on transmitting a pulse consisting of two frequency bands, a low frequency band which purpose is to manipulate the high frequency scattering properties of the contrast agent, and a high frequency band from which the image reconstruction is based. In addition, a general form of pulse subtraction is used to significantly suppress the received tissue signal.

1. Field of the Invention
This invention relates to methods and systems for ultrasonic detection and imaging of contrast agents located in soft tissue or tissue fluids.
2. Description of the Related Art
Ultrasound contrast agents are typically made as solutions of micro gas bubbles or nano lipid particles. The gas bubbles typically show strong and nonlinear scattering of the ultrasound, a phenomenon that is used to differentiate the contrast agent signal from the tissue signal. In the earliest applications (˜1985) the increased scattering from the contrast agent within the transmitted frequency band was used to enhance the scattering from blood. Later, second harmonic components in the nonlinearly scattered signal were used to further enhance the contrast agent signal above the tissue signal in methods generally referred to as nonlinear contrast harmonic imaging.
The following two signal power ratios have vital importance for the quality of performance of a contrast imaging system:                CTR—Contrast signal to Tissue signal Ratio. This gives the ratio of the signal power scattered from the contrast agent in a region to the signal power scattered from the tissue in that region. This ratio is often referred to as specificity.        CNR—Contrast signal to Noise Ratio. This gives the ratio of the signal power scattered from the contrast agent in a region to the noise power in that region. This ratio is often referred to as sensitivity.
The CNR determines the maximum depth for imaging the contrast agent while the CTR describes the enhancement of the contrast agent signal above the tissue signal in the image and thus the capability of differentiating contrast signal from tissue signal. High values of both these ratios are therefore necessary for good imaging of the contrast agent.
The nonlinear distortion of the signal scattered from the contrast agent is much stronger than for the tissue signal, a phenomenon that is extensively used to enhance the CTR. In one method, received tissue signal components in the transmitted frequency band (linear components) are reduced by combining the received signal from two transmitted pulses with different amplitudes. In other methods, the second harmonic band of the nonlinearly scattered signal is obtained either by bandpass filtering or by combining the received signals from two or more transmitted pulses with different polarities.
The contrast agent will typically undergo strong nonlinear oscillations with significant amount of energy scattered at higher harmonic components only if driven into oscillations well below its resonance frequency and the harmonic component used for detection and imaging is often obtained in a bandpass filtering process. To obtain distinct scattered harmonic components, the drive pulse typically has to be relatively narrowbanded. The consequence of a relatively narrowbanded and low frequency drive pulse is the low image resolution typically obtained with harmonic imaging.
Also, the received nonlinear harmonic component from the contrast agent typically has low amplitude which reduces the CNR and may require so high transmitted amplitude that the contrast agent bubbles are destroyed. This can cause a problem when the inflow rate of contrast agent to the tissue region is low.
In addition, nonlinear contrast components scattered in the forward propagation direction will add in phase with the transmit field and hence accumulate. In tissue regions beyond a contrast filled area, these nonlinear contrast components may be linearly back-scattered from the tissue and falsely interpreted as contrast agent signal, hence reducing the CTR. Finally, a limitation in all methods based on nonlinear harmonic detection is that nonlinear components in the tissue signal is preserved in the process, also limiting the CTR.
The new method described does not require nonlinear harmonic imaging and is therefore not constricted by the above mentioned limitations encountered in nonlinear contrast harmonic imaging techniques.

Ultrasonic contrast agent detection and imaging by low frequency manipulation of high frequency scattering properties


A method for installing a heat exchange pipe loop in a borehole, the method, in at least certain aspects, including drilling a borehole with a sonic drill system having a head and casing connected thereto, a drill apparatus on a lower end of the casing movable by the sonic drill head to drill the borehole, pumping fluid into the casing and up to earth surface in an annular space in the borehole so that drilled material flows to the earth surface, lowering a heat exchange pipe loop having a lowermost U/bend member down into the casing, introducing grout into the casing around the heat exchange pipe loop, and extracting the casing from the borehole.

1. Field of the Invention
The present invention is directed to underground heat exchange systems; to apparatus and methods for drilling wellbores for such systems using sonic drilling systems; and to installing underground heat exchange systems.
2. Description of Related Art
The prior art discloses a wide variety of systems for circulating water or refrigerant through pipes in the earth with)the earth serving as a heat sink or heat source heat transfer between the fluid in the pipes and the earth. The prior art discloses numerous in-ground heat exchanger systems; and grouting systems (see, e.g. U.S. Pat. Nos. 5,435,387; 5,244,037; 5,261,251; 5,590,715; 5,758,724; 6,250,371; 6,041,862; and 6,276,438; and pending U.S. application Ser. No. 10/387,125 filed Mar. 12, 2003; and the references cited in these patents and application)—all of which patents, applications therefor, references and application are incorporated here fully for all purposes.
Often the energy efficiency of a geothermal heat pump system is far superior to traditional HVAC alternatives of air source heat pumps, boilers, chillers, furnaces, cooling towers, etc., in many cases requiring fifty percent less energy to operate. One reason why this energy efficient GHP heating/cooling technology is not more widely used is that the initial installed cost is usually higher than for traditional HVAC systems. Often fifty percent or more of the initial cost of a geothermal heat pump system is for constructing an earth loop heat exchanger. Thus it is desirable that the cost of this heat exchanger be kept to a minimum. However, when geological conditions are unusually difficult, drilling and completion costs can dramatically increase, and the cost of installing a geothermal heat pump system can become prohibitive. Thus there is a need, recognized by the present inventor, for a method for the economical construction of a earth heat exchanger which would make possible the widespread use of this energy efficient and environmentally friendly geothermal heat pump technology.
With many prior art systems, the construction of an earth loop heat exchanger has included drilling a borehole 150 to 500 feet deep, inserting a small diameter (usually 0.75 inch to 1.25 inch diameter) polyethylene pipe loop, and grouting the loop in place. Trenches are then dug between such multiple boreholes and earth loop ends are manifolded together in parallel, connected to a common header, and then connected to heat pumps. Water is then circulated through this closed loop system, and heat is absorbed from or transferred to the earth, as the heat pumps require. If so called "direct exchange" heat pump technology is utilized, often copper refrigerant lines are placed in direct contact with the earth, and the heat exchange is accomplished directly with the earth instead of through a secondary water-to-refrigerant heat exchange. Both the more widely used "water source" heat pump technology systems and the direct exchange heat pump technology are available. Both systems are similar insofar as the drilling and completion problems with the earth heat exchangers are concerned.
One typical earth loop heat exchanger design for a small school might require the drilling of 100 holes to a depth of 300 feet, while a large school might require 1000 such holes. High drilling rates and consistent production is preferred for keeping down the costs of the earth heat exchanger. One type of drilling arrangement used to build a geothermal heat exchanger system provides a large number of holes that are relatively deep. Rapid mobilization and set-up between closely spaced holes, fast drilling rates of penetration, and hole stability are critical. However, the drilling technology used in other drilling disciplines is not well-suited or optimized for such geothermal applications. For example, quarry drilling, seismic drilling, and construction drilling all require large numbers of holes in a relatively compact geographic area, but the holes required are relatively shallow in depth, often less than 100 feet deep. In water well drilling and geotechnical investigation drilling, the holes are drilled deeper, but they are relatively small in number. With ancillary operations such as sampling, logging, setting pumps, installing controls and monitoring devices, etc., the speed at which water wells or environmental wells are drilled becomes less critical than it is on geothermal projects.
In addition, many drill rigs are usually designed to drill optimally in only one specific type of formation. Unconsolidated formations such as sand/clay/gravel formations are usually drilled best using mud rotary techniques. The mud rotary drill system utilizes a mud mixing/circulation system incorporating duplex or triplex mud pumps. The drilling mud circulation system transports the drilled spoils out of the hole and also serves to help keep the drilled hole from collapsing. If hard or rock conditions are encountered, drilling progress slows down significantly. If extremely unstable soil conditions are encountered, the mud weight must be regulated carefully to prevent hole collapse and/or to prevent "mining" or over-excavation from occurring.
Constant mud regulation can slow drilling progress significantly. The production rate in mud rotary applications can vary widely and is affected by the formation geology and by the expertise of the driller. The driller is required to know when to thicken up, thin out, or weight up drilling mud; which drill bit to select; what rotation speed to use; how much circulation time is adequate; what additives to put in the mud; and how much pull-down force to apply, etc. These variables can change significantly as the lithology through which drilling is being done changes with increasing depth. In addition, mud drilling can significantly increase the thermal resistance of the borehole in the near-wellbore area by building a wall-cake of poorly thermally conductive bentonite drilling mud—thus requiring additional holes to be drilled.
At another extreme, hard formations such as limestone, sandstone, granite, etc. are usually drilled most economically with downhole hammers powered by compressed air. Even where drilling conditions are predominantly rock, there is usually a layer of unconsolidated overburden on top of the rock which must be penetrated and stabilized before the downhole hammers can effectively begin to drill the rock. If the overburden is very soft or unstable, the top portion of the hole must be supported with casing pipe, usually steel, at least for a depth down to the rock. If the overburden is not stabilized, the top portion of the hole will erode or be "mined out" as the rock is drilled, in extreme cases causing the drill rig to capsize. The expense of traditional overburden drilling and stabilization has made many geothermal projects' cost prohibitive.
Often it is only necessary to case a geothermal borehole temporarily. Once the heat exchanger pipe has been inserted and grouted in place, the casing can be removed. Not only is permanent casing expensive, it can also inhibit the thermal transfer of heat between the heat exchanger pipe and the earth. Even where carousels or magazines automatically handle drill pipe, any casing is often handled manually—using slings, ropes, and cables. In many casing operations, the casing pipe sections are welded together while tripping into the hole and cut apart with a torch as they are extracted from the hole. Besides being a physically demanding job requiring additional labor, the process of loading heavy and clumsy casing pipe is dangerous to personnel. The logistics of handling the casing pipe at the surface usually dictate the use of additional surface equipment such as forklifts, cranes, boom trucks, etc., thus incurring additional equipment rental and labor costs.
It is widely known to drillers skilled in the art that stabilizing a borehole by using steel or other casing is a good and reliable way to ensure borehole integrity. But it is also just as commonly acknowledged that steel casing is usually the most expensive method of stabilizing a borehole, and, because of its high cost, casing is used only as method of last resort. One standard practice of installing casing is to drill a borehole by conventional means, and then insert the casing in the pre-drilled hole. This method presumes that the hole will stand up long enough to insert the casing to the desired depth. However, if the geology is very unstable, which is the primary reason casing is being inserted in the first place, the pre-drilled hole can collapse before casing insertion can be completed. To compensate for this condition, many drilling procedures and special tools have been developed. One of the well-known concepts is simultaneous drilling while casing, in which the casing is advanced as the hole is being drilled. In some prior art systems two sets of tubulars of different diameters, i.e. drill pipe and casing pipe, are simultaneously advanced one inside the other. Often, two independent rotary drillhead mechanisms are employed, each rotating the casing and drill pipe in opposite directions, and each rotary head capable of independent longitudinal travel along a common drill mast. It can be a complex task to effectively insert drill pipe inside casing, present them to two separate drill heads, clamp the different size diameters of pipe while making up and/or breaking out the threaded connections, rotate the pipe and casing in opposite directions while moving them up and down independently. The process is inherently expensive because the machine is very complicated and additional labor and equipment is required to handle the pipe and casing. Drilling production, while reliable, predictable, and fast when compared to first drilling a hole and then setting the casing afterward, is still relatively slow compared to drilling without casing.
Another prior art method of setting casing utilizes a casing hammer to hammer the casing into the ground. Once the casing is hammered in place, the earth inside the casing is drilled out. However, due to the rapid build-up of skin friction between the earth and the casing, the physical limitations of the casing, and the high power required by the hammer, casing driving is slow, and often can only be accomplished to fairly shallow depths. The casing also frequently becomes stuck and/or damaged.
Although sonic drilling principles have been well known for many years, application of these principles has been largely dedicated to specialized areas of geotechnical investigation, mineral sampling, environmental sampling, and monitoring well construction. In these types of drilling, relatively undisturbed core samples of earth are captured inside the casing and recovered for analysis as the drilling progresses. Since the primary emphasis in these types of drilling is on gathering quality soil samples, speed is not essential, and the potential for using sonic drilling for relatively high-speed geothermal borehole production has not been previously considered. In addition, the sonic drillhead and tooling used in sonic drilling can be substantially more expensive than traditional mud rotary or air drilling equipment; and, since geothermal drilling has been normally considered to be very "cheap" drilling work, the investment in "high technology" sonic equipment to drill boreholes has often been discounted as economically prohibitive.

This patent is subject to a terminal disclaimer.

Earth loop installed with sonic apparatus


Semiconductor structures and processes for fabricating semiconductor structures comprising hafnium oxide layers modified with lanthanum oxide or a lanthanide-series metal oxide are provided. A semiconductor structure in accordance with an embodiment of the invention comprises an amorphous layer of hafnium oxide overlying a substrate. A lanthanum-containing dopant or a lanthanide-series metal-containing dopant is comprised within the amorphous layer of hafnium oxide. The process comprises growing an amorphous layer of hafnium oxide overlying a substrate. The amorphous layer of hafnium oxide is doped with a dopant having the chemical formulation LnOx, where Ln is lanthanum, a lanthanide-series metal, or a combination thereof, and X is any number greater than zero. The doping step may be performed during or after growth of the amorphous layer of hafnium oxide.

As future generations of electronic devices advance in complexity and decrease in size, a growing need exists for a dielectric material more effective than SiO2. Increased demands on ultra-large scale integrated (ULSI) circuits have required that the SiO2 that forms the gate oxide of field-effect transistors be made thinner and thinner. Eventually, however, the SiO2 layers will be required to be so thin that electron tunneling will make current leakage unacceptably high for low-power devices.
Amorphous hafnium oxide (HfO2), also known as hafnia, has been identified as a promising candidate to replace SiO2 as a gate dielectric. Hafnium oxide, having a relatively high bulk dielectric constant (k=25), would allow gate oxides to be physically thicker (for a given capacitance), which could significantly reduce tunneling. Hafnium oxide also exhibits a large band gap (approximately 5.7 eV) and a band offset (greater than 1 eV) with substrates such as silicon. Further, the diffusion of hafnium atoms into substrates such as silicon, particularly during or after post-deposition anneals, has proven to be negligible.
However, amorphous hafnium oxide tends to crystallize at relatively low temperatures (approximately 400° C.) to form monoclinic and/or tetragonal crystallites. Polycrystalline hafnium oxide facilitates unwanted metal or impurity diffusion through grain boundaries and degrades gate stack performance. Further, the surface of polycrystalline hafnium oxide is rough, with varied crystal orientation, making it difficult to control the workfunction of the overlying gate metal that is dependent on the surface crystal orientation of the polycrystalline hafnium oxide layer.
Accordingly, it is desirable to provide a semiconductor structure that comprises a modified hafnium oxide layer that exhibits relatively lower leakage current density, higher crystallization onset temperatures and stability in the amorphous phase. In addition, it is desirable to provide a method for fabricating a semiconductor structure that comprises a modified hafnium oxide layer that exhibits relatively higher crystallization onset temperatures and stability in the amorphous phase. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.

Semiconductor structures and methods of fabricating semiconductor structures comprising hafnium oxide modified with lanthanum, a lanthanide-series metal, or a combination thereof


A computer operated man assisted motion generation system for use with a camera in cinematography. The system responds to the measured or sensed position of a camera support such as a crane or dolly, and determines the desired camera pan, tilt, roll, focus, zoom, etc. based on predetermined correspondence between camera location and camera parameters, and generate movement of the camera and camera control accordingly.

There are currently two general systems for operating cameras during cinematography. The first and oldest system is a manual control of the camera and its support platform. Manual control of the camera is provided by a cameraman, and manual control of the support platform is provided by a grip. Before taping a scene, a director instructs actors to move about the set and speak, and perform specified actions. The director also ensures that the scenery, props, and lighting are placed on the set according to his instructions. The director also instructs a camera crew to film the action on the set during a take and capture the action and/or scenery from various viewpoints, with specified camera frames, and to follow the action with specified movements of the camera. The view point is defined by the relationship of the camera to the subject being filmed, and is determined by the location of the support platform and position of any booms or hoist mechanisms used to support the camera. The camera frames are defined by the relationship of the subject being filmed to the entire size of the scene filmed (closeup, portrait, group or landscape are terms that are sometimes used to describe various camera frames). The camera parameters include such things as the pan angle, the tilt angle, and the rotation angle (i.e., spatial attitude of the camera itself) and zoom, aperture, focus and focal length (i.e. lens system attributes). The action is set in motion and is filmed by camera crew, and during filming, the grip will move the support platform to hit the planned view points and the camera operator will adjust the camera parameters to obtain the desired frames follow the action with the specified movements (at the same time, the actors on the set will be moving, speaking and acting according to their own directions).
This is a highly interactive process, and the camera operator and grip must react to variances between the planned action and what actually goes on during each take, and variances between the actual action from take to take. In some situations, this method of filming becomes extremely difficult, and requires great experience and talent for the camera operator and the grip. For example, if the camera support platform is a crane with the camera supported on a remotely controlled camera head, the manual operation of the camera and lens parameters is best performed through remote control, from a remote control panel located at the base of the crane. The pan, tilt and rotation angles are operated by servo-motors at the remote head which adjust these parameters in response to operation of remote control hand wheels. Likewise, the lens system attributes (zoom, focus, etc.) are operated by servo-motors attached to the camera controls, and the servo-motors are operated by input devices on the remote control panel. The remote control panel may consist of a single control panel with controls for all parameters, or separate camera attitude control panel and camera lens system attribute control panel. A typical remote head has hand wheels for adjusting the camera pan, tilt, and rotation.
For a given live action scene, the director may desire viewpoints and camera frames which require large motions of the camera platform and fast motions of some or all of the camera parameters. The number and variety of combinations of such movement are limited only by the creativity of the cinematographer and director. The grip may be required to swing the boom of a camera crane quickly, while the camera operator may at the same time be required to quickly back-pan while slowly adjusting the camera tilt. Thus, for a single operator to adjust these parameters requires simultaneous adjustment and rotation of the hand wheels, but at varying speeds and directions for each hand wheel. This is quite difficult, akin to rubbing your tummy while patting your head, and maybe hopping up and down, where the patting occurs at one speed, the rubbing occurs at another speed, and the hopping occurs at yet another speed.
Another way to film a scene is through the use of computer operated motion control systems. These systems are ideal for reproducing exactly the same camera movement over and over again, which is desirable in special effects creation. The ability to film the exact same sequence, over and over again, helps cinematographers and producers produce special effects in which many images are layered on top of each other. Examples of the special effects created with motion control systems are the various space battle scenes in which numerous spaceships fly about on diverse flight paths while the camera follows one of the space ships. This type of special effect is created by filming a first scene in which the model central ship flies through a model stage while the camera follows the ship as desired. After this first scene is filmed, another scene is taped in which a model second ship flies through the model stage, and it is filmed by the camera while the camera proceeds along the exact same pathway to capture this second scene. The two films are then layered together to make a single film showing both ships together. Any number of ships may be added to the scene by taping additional ships while the camera repeats its path exactly for every take. In order for the movement of the various ships to appear responsive to each other, and to permit accurate overlays, the different films must be synchronized. Battle scenes such as the spectacular Star Wars dog fight between Luke Skywalker and Darth Vader in the trench of the Death Star were created using this type of system.
Typical motion control systems, such as those used by Industrial Light and Magic, and those produced by Mark Roberts Motion Control or Christopher Nibley Cinematographers, control every parameter of both the crane and camera operation. The movement of the crane along a track, the speed of the crane movement, the boom tilt, boom extension and crane rotation, as well as camera pan, tilt, rotation, zoom, aperture and focal length are all controlled by the computer. In these systems, a key frame method may be used to establish the several points along the desired path of the crane and camera. The crane is moved to a number of key positions, the camera attitude adjusted to a number of corresponding key attitudes, and the camera controls adjusted to obtain a key frame defined by the camera parameters. These key frames are selected by the director, and the key frame is defined by certain predetermined field of view, focal length, focus and orientation of the scene on the film. This key frame corresponds to the zoom, camera attitude, and camera position and crane position used to view the key frame. In the key frame motion control system, the system memorizes all the parameters of the key frame, and receives input from the system operator on the desired predetermined time to hit each key frame. When the system is instructed to start a take, it moves the camera to the key frames at the predetermined times. The camera may interpolate movement between the key frames to ensure a smooth trajectory of the camera between key frames. The key frames are hit at the same time in every take, and we refer this as a synchronized system because the key frames and all other frames are strictly tied to a master clock to ensure that the camera movement proceed not only through the same points, but also at the same pace, on every take.
These motion control systems completely eliminate operator input during the take. The advantage of this system is that it can repeat complicated camera movements very precisely, and many times over, with no deviation in the movement of the camera from one take to the next. On the other hand, the system does not permit modification of the camera movement during the take, because it is not intended for use in live action where it is desirable to modify the camera movement from the predetermined camera movement during the take.
For filming of many live action scenes, manual manipulation of the camera is exceedingly difficult. The artistically desired pace and movement of the camera between viewpoints may require extremely rapid manipulation of the camera controls. While a talented cameraman may be able get the shot, the need to film several takes of the same scene due to limitations in the camera operator's work, the grips work, the actors' performance and the motion of other subjects such as vehicles and animals increases the workload, and a system that provides assistance to the cameraman facilitates production. Use of a motion control system as described above is not a feasible solution, because the camera movement and operation is fixed by the system and cannot be altered to account for variations in the performance as a cameraman can.


The toothed rack steering gear has an adjusting nut and a housing. An opening with internal thread of the housing is adapted to the adjusting nut and receives the adjusting nut in the assembled state. In the housing at least one recess is provided in direct proximity of the opening. A retainer is provided; it has a ring shaped body and at least one finger. The finger protrudes from this ring shaped body and can engage into the recess. The retainer has a back surface and the adjusting nut has a front surface. In the assembled state both are in contact. A connecting device is provided and secures the connection between the back surface and the front surface.

The invention refers to a toothed rack steering gear, as well as to a procedure for the production of such a toothed rack steering gear.
Toothed rack steering gears are used widely with motor vehicles, for the state of the art it is referred to GB 2174474 A and DE 3151835 C2. The known toothed rack steering gear has a housing, in this housing a pinion shaft is arranged and is rotatable around an axle. This pinion shaft is in connection with a toothed rack, which is lodged in the housing and can be adjusted in axial direction. An elastic means, which may also be designated as a counter-pressure mechanism, is provided; this means compensates the reaction forces between the pinion shaft and the toothed rack. It has a thrust piece and an adjusting nut, a compression spring is arranged there between. For the correct function the adjusting nut is adjusted in such a way that an adjusted play gap S is provided between the adjusting nut and the thrust piece.
The adjusting nut closes and locks the opening of the housing in the assembled state. The adjusting nut may therefore be designated as a locking nut. It usually has a drive portion; an adjusting tool can attach at that drive portion, for example a hexagonal wrench.
The adjusting nut must be fixed in the adjusted position and/or secured. Thus the adjusting nut is prevented to become unadjusted.

Ultrasonic welded plastic retainer to secure yoke plug adjustment


A suede-like micro-fibril finish is imparted to fibrillatable cellulosic materials by open width hydraulic treatment. Additional enhancement of the fabric finish is obtained by post hydraulic enzyme and wet processing treatments. Fluid treated fabrics of the invention are characterized by substantially uniform fibrillation of fibers within the fabric body and surface areas.

Lyocell is a natural cellulosic fiber spun from an amine oxide solvent developed by American ENKA, Asheville, N.C. in the late 1970's. Courtaulds Fibers Inc. of Axis, Ala. ("Courtaulds") markets lyocell fiber under the brand name TENCEL in lengths suitable for short-staple and worsted and woolen spinning systems. TENCEL has a highly crystalline structure and is fabricated from an amine oxide solvent of N-methylmorpholine N-oxide, commonly referred to as NMMO. The industry has found that TENCEL materials are superior to other cellulosics, including cotton and rayon in tensile and aesthetic properties which make it suitable for use in the textile field.
A wide diversity of fabric finishes may be imparted to lyocell fabrics by employing wet processing and enzyme finishing techniques which "fibrillate" the fibers in the fabric. Fibrillation is the formation of micro-fibrils on the surface of fibers as a result of mechanical abrading or splitting of the fiber. It is well known in the textile field that wet processing techniques can be employed to control fibrillation to obtain aesthetic effects.
Courtaulds provides recommended wet processing conditions for finishing TENCEL fabrics. In general, the preferred processing techniques consist of initial wet processing to fibrillate surface fibers in the fabric, an enzyme treatment to remove the surface fibrillation, and a secondary wet processing to fibrillate fibers in the fabric body to provide a "peach skin" or suede fabric finish. Additional recommended processing includes use of scouring techniques, caustic agents and softeners.
Conventional lyocell wet processing techniques have not proven entirely satisfactory because they require long duration washing cycles and controlled enzyme treatments to obtain useful results. It is also found that conventional processing does not consistently yield uniform finishes in lyocell fabrics.
Hydroenhancement techniques have been developed for enhancing the surface finish and texture, durability, and other characteristics of woven or knit spun and spun filament yarn fabric. For example, such techniques are described in commonly owned U.S. Pat. Nos. 4,967,456 and 5,136,761 of H. Sternlieb et al. The hydroenhancing process generally includes exposing one or both surfaces of a fabric to fluid jet treatment, followed by removal of moisture from the fabric and drying. During hydroenhancement, the high pressure water jets impact the spun yarns and cause them to bulk or bloom and the fibers in the yarn to become interentangled. Fabrics produced by this hydraulic treatment process have enhanced surface finish and improved characteristics such as cover, abrasion resistance, drape, stability as well as reduced air permeability, wrinkle recovery, seam slippage and edge fray.
It will be recognized by those skilled in the art that it would be advantageous to provide an hydraulic process for continuous production line finishing of lyocell fabrics. However, it has been the general view in the field that such processing is not suitable for promoting adequate fibrillation in lyocell fabric. For example, Courtaulds, technical manual, Dyeing and Finishing TENCEL Fabrics in Garment Form, states that "open width" fabric processes do not fibrillate TENCEL fabrics.
The present invention resides in the discovery that hydraulic treatment, when optimized with respect to specifications of the fluid curtain and process conditions, unexpectedly produces pre-cursor fabrics suitable for further finishing treatment by wet processing techniques. Advantageously, it is found that hydraulic treatment promotes fibrillation in lyocell fabrics and yields process efficiencies in further wet process finishing. Hydraulic processing in accordance with the invention also yields improvements in fabric properties.
Accordingly, it is a broad object of the present invention to provide an hydraulic treatment finishing process for lyocell fabrics.
A more specific object of the invention is to provide an hydraulic treatment process which uniformly fibrillates and improves physical properties of lyocell fabrics.
A further object of the invention is to provide an hydraulic production line apparatus which is less complex and improved over the prior art.

Uniformity and product improvement in lyocell garments with hydraulic fluid treatment


A process comprising substitution of an acceptor molecule comprising a group —XC(O)— wherein X is O, S, or NR8, where R8 is C1-6 alkyl, C6-12 aryl or hydrogen, with a nucleophile, wherein the acceptor molecule is cyclised such that said nucleophilic substitution at —XC(O)— occurs without racemisation, is provided. This process has particular application for the production of a peptide by extension from the activated carboxy-terminus of an acyl amino acid residue without epimerisation.

The present invention relates to a novel process for peptide synthesis, by the addition of amino acids to the activated C-terminus of a peptide chain. Peptide synthesis is central to the manufacture of many drugs and medicaments. Peptides or derivatives thereof are used for the treatment of many disorders from antibiotics to anticancer agents. Therefore improving peptide synthesis and the yield of peptide produced by chemical synthesis has been the focus of much research in recent years.
Chemical synthesis of proteins or peptides has been a particular focus in the art. The chemical synthesis of proteins or peptides allows the production of purified peptides of specific amino acid sequence. It also allows the production of truncated sequences of amino acids and allows the introduction of non-natural amino acid derivatives.
Proteins are produced in nature by the stepwise condensation of amino acid monomers on a ribosome. Synthesis of the protein begins from the N-terminal residue and grows towards the C-terminus. The conventional approach to peptide synthesis has concentrated on extension at the N-terminus of a growing peptide. This approach forms the basis of conventional solid phase peptide synthesis. Peptide synthesis solely by extension from the N-terminus is limiting as it renders any peptide synthesis lineal in nature, rather than convergent. This can severely increase overall length of synthesis, increase operational time and decrease overall yield with consequent possibilities for the loss of stereochemical fidelity.
To overcome the problems associated with N-terminal extension of a peptide, it could be envisaged that the synthesis could instead provide extension of a peptide from the C-terminal. However, attempts at peptide synthesis in the N to C direction have been generally unsuccessful due to epimerisation of the carboxy-terminal amino acid residue. This is due to the tendency of carboxy-terminal-activated acylamino acids and peptides to form oxazolones. As illustrated below, the formation of the oxazolone allows rapid racemisation of the alpha-position of the terminal amino acid residue of the acyl amino acid or peptide.

This racemisation prevents the production of stereochemically homogeneous peptides by C-terminus extension.
It will be appreciated that the production of isomerically pure compounds is a particular requirement in the art. Any method which results in the production of a mixture of isomers will require the use of time consuming and expensive purification steps to separate the isomers. Chiral compounds which are administered to humans or animals are usually required in enantiomerically pure form. The presence of unwanted isomers even in low concentrations can reduce the potency of the compound and can produce unwanted and in some cases disastrous side effects. The incorporation of an unwanted enantiomer into a peptide chain (for example the incorporation of a D-amino acid into a peptide composed of L-amino acids) may disrupt the folding and/or 3D shape of the peptide, thus resulting in a peptide which may have unpredictable binding activities and/or biological properties. The production of enantiomerically pure peptides is therefore of paramount importance.
Various attempts have been made to overcome this problem. Iorga, B and Campagne, J-M (2004, Synlett 10, 1826-1828) attempted to reduce the degree of epimerisation by improving the rate of peptide bond formation over the rate of oxazolone formation so that peptide bond formation was the predominant reaction. However, this method does not entirely prevent the formation of the oxazolone and therefore epimerisation at the carboxy-terminal activated amino acid residue occurs. Native chemical ligation has been developed to overcome problems of carboxy-terminal extension but is ordinarily restricted to couplings in which the amino-terminal partner is an assisting cysteine residue and is not applicable to general techniques of automated solid phase peptide synthesis. The application of native chemical ligation to other amino-terminal amino acids has had very limited success.
The present invention provides a new method of producing a peptide by extension from the activated carboxy-terminus of an acyl amino acid residue. This new method overcomes the problems of epimerisation of the terminal amino acid residue during the coupling step. The present invention therefore allows the production of peptides by a convergent approach and provides a new method for the production of potentially biologically important compounds instead of the linear repetitive amino terminal extension approach currently used.
The first aspect of the present invention provides a process comprising substitution of an acceptor molecule comprising a group —XC(X)— (preferably —X(CO)—) wherein each X is independently O, S or NR8, where R8 is hydrogen, aliphatic group or an aromatic group, preferably hydrogen, C1-6 alkyl, C6-12 aryl, with a nucleophile, wherein the acceptor molecule is cyclised such that said nucleophilic substitution at —XC(X)— occurs without racemisation. The acceptor molecule is preferably a cyclised amino acid or derivative thereof. In particular, the acceptor molecule is a compound of formula (II):
wherein each X is O, S, or NR8, where R8 is as defined above;R2 is independently selected from an aliphatic group, such as a C1-10 branched or straight chain alkyl group, or an aromatic group, such as C5-12 heteroaryl group or C6-12 aryl group, each optionally substituted with a group including, for example, OR13, SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2;R3 is as defined for R2 or is hydrogen,or a group
or a group
a group —C(R1′)(R9)—N(R10)(R11);wherein R1′ is independently selected from an aliphatic group such as C1-10 branched or straight chain alkyl group, an aromatic group, such as C5-12 heteroaryl group or C6-12 aryl group, each optionally substituted with a group such as OR13SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2;wherein when Y is NR8, R8 and R1′ can together form a 4 to 7 membered ring, optionally substituted with a group such as CO2R13, OR13, SR13, N(R13)2, CO2R13, CON(R13)2, C1-10 alkyl or C6-12 aryl, wherein said ring can be fully, partially or unsaturated, and wherein the ring may contain one or more additional heteroatoms selected from O, S or N;R12 is hydrogen, C1-6 alkyl C6-12 aryl or N(R13)2, wherein each occurrence of R13 is independently hydrogen, C1-6 alkyl or C6-12 aryl, and R4′ is a carboxyl protecting group or hydrogen;R9 and R10 are independently hydrogen or a group as defined for R1′;R11 is hydrogen or an amino protecting group preferably selected from a benzyloxycarbonyl group, a t-butoxycarbonyl group, a 2-(4-biphenylyl)-isopropoxycarbonyl group, a fluorenylmethoxycarbonyl group, a triphenylmethyl group and/or a 2-nitrophenylsulphenyl group;or R9 and R10 or R10 and R11 or R1′ and R10 or two R13 can together form a 4 to 7 membered ring, optionally substituted with a group such as CO2R13, OR13, SR13, N(R13)2, CO2R13, CON(R13)2, C1-10 alkyl or C6-12 aryl, wherein said ring can be fully, partially or unsaturated, and wherein the ring may contain one or more additional heteroatoms selected from O, S or N;Y is O, S or NR8, where R8 is as defined above;YR4′ is R3;R5 is an aromatic group such as C6-12 aryl, C5-12 heteroalkyl or an aliphatic group such as C1-8 branched or straight chain alkyl optionally substituted with a group such as OR13, SR13, N(R13)2, CO2R13, CON(R13)2, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2 or a linker for attachment of formula (II) to a resin or a linked resin;n is 0, 1, 2 or 3 and m is an integer, such as an integer selected from 1-100.
The nucleophilic substitution of the acceptor molecule preferably occurs without epimerisation.
Preferably, the process is carboxy terminal extension of an acceptor molecule, for example an amino acid or peptide. The invention therefore provides a process for the synthesis of a peptide or a peptide analog by carboxy terminal extension, by the addition of a nucleophile to an acceptor molecule such as a compound of formula (II).
There is further provided a process for the production of a compound of formula (I)
comprising reaction of a compound of formula (II) or (II′) (above)
with a compound of formula (III)HY—R7  (III)wherein the variables are defined as above:preferably X is O, S, or NR8, where R8 is as defined above, Y is O, S or NH;R2 is independently selected from a C1-10 branched or straight chain alkyl group, C5-12 heteroaryl group or C6-12 aryl group, optionally substituted with OR13, SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2;R3 is as defined for R2 or is hydrogen, or a group
or a group —C(R1′)(R9)—N(R10)(R11);wherein R1′ is hydrogen or as defined from R1 below; Y is as defined above and R4 is as defined for R4 below;R12 is hydrogen, C1-6 alkyl, C6-12 aryl or N(R13)2, wherein each occurrence ofR13 is independently hydrogen, C1-6 alkyl or C6-12 aryl,R9 and R10 are independently hydrogen or a group as defined for R1′;or R9 and R10 can together form a 4 to 7 membered ring, optionally substituted with CO2R13, OR13, SR13, N(R13)2, CO2R13, CON(R13)2, C1-10 alkyl or C6-12 aryl, wherein said ring can be fully, partially or unsaturated, and wherein the ring may contain one or more additional heteroatoms selected from O, S or N,R11 is hydrogen or an amino protecting group preferably selected from a benzyloxycarbonyl group, a t-butoxycarbonyl group, a 2-(4-biphenylyl)-isopropoxycarbonyl group, a fluorenylmethoxycarbonyl group, a triphenylmethyl group and/or a 2-nitrophenylsulphenyl group;R5 is an aromatic group, such as C5-12 aryl, C5-12 heteroalkyl or an aliphatic group, such as C1-8 branched or straight chain alkyl optionally substituted with OR13, SR13, N(R13)2, CO2R13, CO N(R13)2, phenyl, imidazolyl, indolyl, hydroxyphenyl orNR13C(═NR13)N(R13)2 or a linker for attachment of formula (II) to a resin or a linked resin; R6 is hydrogen or
wherein R5 and X are as defined above;R7 is a chiral, substituted methylene, such as a group
or is independently selected from an aliphatic group such as a C1-10 branched or straight chain alkyl group or an aromatic group, such as a C6-12 aryl group, optionally substituted with OR13, SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2);or wherein R7 and Y together form a 4 to 7 membered ring, optionally substituted with a group such as OR13, SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2, wherein said ring can be fully, partially or unsaturated, and wherein the ring may contain one or more heteroatoms in addition to Y, selected from O, S or N;wherein R1 is R1′ or is independently selected from an aliphatic group such as C1-10 branched or straight chain alkyl group, or an aromatic group such as C5-12 heteroaryl group or C6-12 aryl group optionally substituted with a group such as OR13, SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2;and R4 is R4′ or a carboxyl protecting group or hydrogen; n is 0, 1, 2 or 3 and m is an integer such as a value selected from 1-100 and when n=0, R6 is H.
The inventors have surprisingly found that activation of an amino acid or peptide via a cyclic compound as exemplified in formula (II) prevents the formation of an oxazolone thereby allowing the condensation of a compound of formula (III) without concommitant epimerisation. The invention therefore provides peptides via C-terminus extension, said peptides being produced in an enantiomerically and diastereochemically pure form.
The use of activated cyclic N-acyl amino acids, peptides or derivatives thereof eliminates oxazolone formation and associated epimerisation. The use of cyclic activated intermediates in the present invention provides an improved method of peptide synthesis via carboxy-terminal extension.
Therefore, rather than merely reducing the probability of epimerisation occurring, as has been attempted in the prior art, the process of the present invention does not permit epimerisation and therefore guarantees the production of a peptide of correct stereochemistry as the activated carboxyl terminus is held in a cyclic template such that the adjacent amide cannot form the oxazolone.
In accordance with usual practice, * denotes a stereocenter (asymmetric center). Where a compound contains a stereocenter (whether marked in the present application with * or not) the stereochemistry of the asymmetric centers may be in the R or S configuration. The compounds of the present application can be provided in enantiomerically pure form or as a mixture of isomers (including a racemic mixture). Preferably, the compounds of the present inventions are provided in an enantiomerically pure form. The present invention allows maintenance of the desired stereochemistry throughout the synthetic pathway. Thus wherein Y is NH, the amino acids to be attached may be of L or D configuration as required.
Preferably R1 and R2 are independently selected from C1-4 branched or straight chain alkyl optionally substituted with OR13, SR13, N(R13)2, CO2R13, CON(R13)2, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2, preferably optionally substituted with OH, SH, NH2, CO2H, CONH2, phenyl, imidazolyl, indolyl, hydroxyphenyl or NH(C═NH)NH2.
More preferably, R and R are independently selected from C1 alkyl optionally substituted with OH, SH, CO2H, CONH2, phenyl, imidazolyl, indolyl or hydroxyphenyl; C2 alkyl optionally substituted with OH, CO2H, CONH2 or SCH3; C3 alkyl optionally substituted with NHC(═NH)NH2 or C4 alkyl optionally substituted with NH2.
The integer, m is preferably 1-50, more preferably 1 to 30, most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20. The integer n is preferably 0 or 1.
When X is NR, R is preferably Ci−4 alkyl more preferably methyl, ethyl, n-propyl, iso-propyl, n-butyl or tert-butyl, phenyl, naphthyl, anthracenyl or phenanthracenyl, more preferably phenyl or hydrogen.
R3 may also be substituted pipecolic acid or derivative thereof, α-alkoxy-α-amino acids, α,α-diamino acids, β-substituted dehydroamino acids, canavanine, cysteinesulphonamide, homocysteinesulphonamide, γ,δ-unsaturated amino acids, substituted 4-hydroxyprolines, 4-hydroxtyornlithines, imino sugars, Fmoc-BPC—OH, Fmoc-TPG-OH and Fmoc-CAA-OH, or (5)-3,5-dihydroxyphenylglycine.
It will be appreciated by a person skilled in the art that amino acids, hydroxy acids and derivatives thereof contain functional groups which require protection. In particular it is known in the art to protect the amino terminus, the carboxyl terminus and/or the side chains of an amino acid or peptide (for example wherein R1 or R2 is CH2CO2H or CH2CH2OH). Examples of such protection are well known in the art. In particular the amino terminus of an amino acid may be protected by one or more of a benzyloxycarbonyl group, a t-butoxycarbonyl group, a 2-(4-biphenylyl)-isopropoxycarbonyl group, a fluorenylmethoxycarbonyl group, a triphenylmethyl group and/or a 2-nitrophenylsulphenyl group. The carboxyl group can be protected by one or more of an ester group especially a methyl, ethyl, benzyl, t-butyl or phenyl ester. Thus R4 is preferably methyl, ethyl, benzyl, t-butyl or phenyl.
Conditions for the removal of the protecting groups discussed above are well known in the art. The protecting groups may be removed after each coupling reaction (for example, the carboxyl protection) or alternatively at the end of the synthesis (for example, the side chain protection and/or the N-terminal group).
In a particular feature of the first aspect, the invention provides a process for production of a compound of formula (Ia)
comprising reacting a compound of formula (IIa) (above)with a compound of formula (III) HY—R7;Wherein the groups Y, X, R2, R3, R5, and R7 are as defined above.In an alternative feature of the first aspect, the invention provides a process for production of a compound of formula (Ib)
comprising reacting a compound of formula (IIb)
with a compound of formula (III) HY—R7 wherein the groups Y, X, R2, R3, R5 and R7 are as defined above for compounds (I), (II) and (III).
The N and the terminal ester of formula (I), (Ia) or (Ib) can be unmasked by processes known in the art, for example, sodium liquid ammonia in the presence of an alcohol when R1=phenyl and R4=t-butyl. Alternatively, the ester can be further derivatized, including for example, amidation.
The nucleophilic substitution of the acceptor molecule of the first aspect of the invention can be carried out using reaction conditions known in the art. In some circumstances, for example where the nucleophile and/or the acceptor molecule are sterically hindered it may be necessary for example to use high pressure such as around 19-20 bar, and/or longer reaction times such as 12-72 hours, preferably 24-48 hours. Alternatively, the reaction can be carried out in the presence of a reagent such as AlMe3. When the substitution is carried out on the solid phase, the reaction can be promoted by the use of an excess of nucleophile.
The invention further relates to a process for the production of a compound of formula (II) (above) by the reaction of a compound of formula (IV)
with a compound of formula (V) Z—CO—R3 wherein Z is any substituent capable of being involved in peptide bond formation preferably hydroxide, halide or azide, and R2, R3, R5, X and n are as defined above. It will be appreciated that when R3 is a protected peptide, subsequent N-terminus extension may be carried out using peptide synthesis methods known in the art, such as deprotection and further peptide bond formation.
The process of the present invention can particularly be used for the production of cyclic compounds, for example cyclic peptides.
It will be appreciated that when R3 is C(R1′)(R9)—N(R10)(R11), the compound of formula (II) can be reacted with one or more compounds of formula (V) in a stepwise direction.
The present invention therefore encompasses a compound of formula (VII);
wherein the variables are described above, preferably m is an integer of 1 to 50, preferably 1 to 30, more preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20; and R1′, R2, R5, R9, R10, R11, X and n are as defined above.
The compound of formula (VII) can be used in a process for the formation of a compound of formula (I) (illustrated below as (Ic));
when R14 is —[C(O)—C(R9)(R1′)—N(R10)—]m—(R11) and R1′, R2, R6, R7, R9, R10, R11, m, X and Y are as described above, comprising, reaction of a compound of formula (VII) with a compound of formula (III) as described above. The compound of formula (I) can then be converted into a compound of formula (VI) by removal of the group R6 as described below. For the compound of formula (VII) and compounds of formula (I) or (VI) obtained therefrom, the substituents R1 and R9 can be replaced by a group (═R1) wherein R1 is as described above.
It will be appreciated that when m is 3 or more, and R10 and R11 are hydrogen, condensation can occur at the X—C(O)— functionality of the compound of formula (VII) to form a cyclised compound of formula (VIII);
wherein the variables are as defined above.
The present invention therefore provides a compound of formula (VIII). In addition, the invention provides a process for the production of a compound of formula (VIII) comprising cyclisation of a compound of formula (VII) wherein m is 3 or more. Reaction of the compound of formula (VIII) under reducing conditions (for example in the presence of lithium and liquid ammonia) results in the formation of a compound of formula (IX);
wherein R1′, R2, R9, X and m are as defined above.
The present invention therefore provides a compound of formula (IX) and a process for the production of a compound of formula (IX) comprising the reduction of a compound of formula (VIII).
It will be appreciated that the process of the present invention can be carried out in solution. Alternatively, a compound of formula II may be attached to a resin via the group R5 and the peptide synthesis carried out via solid phase peptide synthesis. When R5 is a linker it can be a group OR13, N(R13)2, CO2R13 or SR13, or an alkyl group having 1 to 4 carbons or a C6-12 aryl group, said alkyl and aryl groups being optionally substituted with OR13, N(R13)2, CO2R13 or SR13. Alternatively, part of the synthesis may be carried out on the solid phase and part in solution.
The compound of formula II can be attached to and removed from a resin using methods known in the art.
Solid phase peptide synthesis using the process of the present invention may be carried out by using procedures attaching the carboxy-terminal to any resin known in the art. Examples of suitable resins include Wang, Merrifield, polyamide, 2-chlorotrityl, Rink, Knorr, DCHD, PAL and any other known in the art. Solid phase coupling partners such as BOP, PyBOP) and DCC may be used, as well as any other suitable coupling partners known in the art.
A further feature of the first aspect is a process for the production of a compound of formula (VI)
from formula (I)
by the removal of R6 by any method known in the art, wherein X, Y, R2, R3, R6 and R7 are as defined above. It will be appreciated that when R6 is hydrogen, the compound of formula (I) corresponds to the compound of formula (VI).
In particular, the removal of the group R6 may be carried out under reducing conditions such as under Birch conditions (i.e. with lithium and liquid ammonia). As it will be appreciated by the skilled person, the peptide produced by the process of the first aspect may be post modified by any suitable method known in the art. A second aspect of the present invention relates to the compounds described herein, including a compound of formula (II)
wherein X is O, S or NR8, where R8 is C1-6 alkyl C6-12 aryl or hydrogen R2 is independently selected from a C1-10 branched or straight chain alkyl group, C5-12 heteroaryl group or C6-12 aryl group, optionally substituted with OR13, SR13N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12 phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2; R3 is as defined for R2 or is hydrogen, or a group
or a group —C(R1′)(R9)—N(R10)(R11) wherein R1 is independently selected from a C1-10 branched or straight chain alkyl group, C5-12 heteroaryl group or C6-12 aryl group optionally substituted with OR13, SR13, N(R13)2, CO2R13, CON(R13)2, SO2R12, SO3R12, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2 wherein when Y is NR8, R8 and R1′ can together form a 4 to 7 membered ring, optionally substituted with CO2R13, OR13, SR13, N(R13)2, CO2R13, CON(R13)2, C1-10 alkyl or C6-12 aryl, wherein said ring can be fully, partially or unsaturated,and wherein the ring may contain one or more heteroatoms selected from O, S or N; R12 is hydrogen, C1-6 alkyl, C6-12 aryl or N(R13)2, wherein each occurrence of R13 is independently hydrogen, C1-6 alkyl or C6-12 aryl, R9 and R10 are independently hydrogen or a group as defined for R1; or R9 and R10 can together form a 4 to 7 membered ring, optionally substituted with CO2R13, OR13, SR13, N(R13)2, CO2R13, CON(R13)2, C1-10 alkyl or C6-12 aryl, wherein said ring can be fully, partially or unsaturated, and wherein the ring may contain one or more heteroatoms selected from O, S or NR11 is hydrogen or an amino protecting group preferably selected from a benzyloxycarbonyl group, a t-butoxycarbonyl group, a 2-(4-biphenylyl)-isopropoxycarbonyl group, a fluorenylmethoxycarbonyl group, a triphenylmethyl group and/or a 2-nitrophenylsulphenyl group; R1 is independently selected from C1-10 branched or straight chain alkyl optionally substituted with OR13, SR13, N(R13)2, CO2R13, CO N(R13)2, phenyl, imidazoyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)3 and R4′ is a carboxyl protecting group or hydrogen and n is 0, 1, 2 or 3, m is 1-100; and R5 is a linker for attachment of formula (II) to a resin, a linked resin, or C6-12 aryl, C5-12 heteroalkyl or C1-8 branched or straight chain alkyl optionally substituted with OR13, SR13, N(R13)2, CO2R13, CON(R13)2, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2; wherein when X═O, and R5 is phenyl, n is not 0 or 1.
Preferably R1 and R2 are independently selected from C1-4 branched or straight chain alkyl optionally substituted with OR13, SR13, N(R13)2, CO2R13, CON(R13)2, phenyl, imidazolyl, indolyl, hydroxyphenyl or NR13C(═NR13)N(R13)2. More preferably R1 and R2 are independently selected from C1 alkyl optionally substituted with OR13, SR13, CO2R13, CO N(R13)2, phenyl, imidazolyl, indolyl or hydroxyphenyl; C2 alkyl optionally substituted with OR13, CO2R13, CON(R13)2 or SCH3; C3 alkyl NR13C(═NR13)N(R13)2 or C4 alkyl optionally substituted with N(R13)2.
As set out above, R4 is a carboxyl protecting group, such as an ester group. In particular R4 is preferably methyl, ethyl, benzyl, t-butyl or phenyl. When R5 is a linker it can be OR13, N(R13)2, CO2R13 or SR13 or an alkyl group having 1 to 4 carbons or a C6-12 aryl group, wherein the alkyl group and/or aryl group can be substituted with one or more of OR13, N(R13)2, CO2R13 or SR13.
The integer, m is preferably 1-50, more preferably 1 to 30, most preferably 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20. The integer n is preferably 0 or 1.
When X is NR8, R8 is preferably C1-4 alkyl, more preferably methyl, ethyl, n-propyl, iso-propyl, n-butyl or tert-butyl, phenyl, naphthyl, anthracenyl or phenanthracenyl, more preferably phenyl or hydrogen.
R13 is preferably hydrogen or C1-4 alkyl, more preferably methyl, ethyl, n-propyl, iso-propyl, n-butyl or tert-butyl.
For the purposes of this invention, alkyl relates to both straight chain and branched, saturated or unsaturated alkyl radicals having, for example, 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms and most preferably 1 to 4 carbon atoms including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl n-pentyl, n-hexyl, n-heptyl, n-octyl. Alkyl therefore relates to a group having 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 or more carbon atoms. The term alkyl also encompasses cycloalkyl radicals of 3 to 12 carbon atoms, preferably 4 to 8 carbon atoms, and most preferably 5 to 6 carbon atoms including, but not limited to cyclopropyl, cyclobutyl, CH2-cyclopropyl, CH2-cyclobutyl, cyclopentyl or cyclohexyl. Cycloalkyl groups may be optionally substituted or fused to one or more carbocyclyl or heterocyclyl group. Haloalkyl relates to an alkyl radical preferably having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms substituted with one or more halide atoms for example CH2CH2Br, CF3 or CCl3. An alkyl group may be optionally interrupted by one or more O, S or NH groups, preferably one or more O atoms to form an alkoxy group. An alkyl group may be optionally interrupted by one or more double or triple bonds to form a group including but not limited to ethylene, n-propyl-1-ene, n-propyl-2-ene, isopropylene, ethynyl, 2-methylethynyl etc.
"Aryl" means an aromatic 6 to 12 membered hydrocarbon or heteroaryl containing one ring or being fused to one or more saturated or unsaturated rings including but not limited to phenyl, naphthyl, anthracenyl or phenanthracenyl. "Heteroaryl" means an aromatic 5 to 12 membered aryl containing one or more heteroatoms selected from N, O or S and containing one ring or being fused to one or more saturated or unsaturated rings including but not limited to furan, imidazole, indole, oxazole, purine, pyran, pyridine, pyrimidine, pyrrole, tetrahydrofuran, thiophene and triazole. The aryl and heteroaryl groups can be fully saturated, partially saturated or unsaturated.
Halogen means F, Cl, Br or I, preferably F.
A third aspect of the invention relates to the use of a compound of formula (II) as defined in the first and/or second aspects of the invention in asymmetric synthesis.
All preferred features of each of the aspects of the invention apply to all other aspects mutatis mutandis.
The present invention will now be illustrated by reference to one or more of the following non-limiting examples:


The present disclosure provides a method for stacking of a plurality of optical fibre ribbons (106). The plurality of optical fibre ribbons (106) is defined by a top surface (S1) and a bottom surface (S2). The top surface (S1) and bottom surface (S2) are defined by a plurality of elevated regions and a plurality of groove regions. The method for stacking of the plurality of optical fibre ribbons (106) includes arranging the plurality of optical fibre ribbons (106) over each other such that the plurality of elevated regions of each of the plurality of optical fibre ribbons fits over the plurality of groove regions of an adjacent optical fibre ribbon of the plurality of optical fibre ribbons (106). In addition, arrangement of the plurality of optical fibre ribbons forms an optical fibre ribbon stack (200).

With the advancement of science and technology, various modern technologies are being employed for communication purposes. One of the most important modern communication technologies is the optical fibre communication technology using a variety of optical fibre cables. One such type of optical fibre cables are optical fibre ribbon cables. These optical fibre ribbon cables may include a large number of optical fibre ribbons and may have a large diameter that makes the optical fibre ribbon cable difficult to install in ducts having a small diameter. Each optical fibre ribbon includes a number of optical fibres placed adjacent and bonded together with a matrix material. The currently available optical fibre ribbons have certain drawbacks. Cables made with existing optical fibre ribbons have a larger diameter causing installation of optical fibre ribbon cable in ducts to become difficult.
In light of the foregoing discussion, there exists a need for an optical fibre ribbon which overcomes the above cited drawbacks of conventionally known optical fibre ribbons.

Optical fibre ribbon and optical fibre cables thereof


A cleaning solution for removing copper complex residues from the surface of polishing pads and wafer substrates includes an amine pH-adjusting agent, which can be a unidentate or bidentate amine compound or a quartnary ammonium hydroxide compound or an amine including an alcohol group. The cleaning solution also includes an amino acid complexing agent and an inhibitor. In a preferred embodiment, the cleaning solution has a basic pH.

Silicon wafers are widely used as substrates on which multilevel integrated circuits are fabricated. Integrated circuits on a semiconductor wafer are typically manufactured with insulating layers, semiconductive layers, such as polysilicon, and conductive metals substrate layers, such as tungsten, aluminum, copper and platinum. The dielectric materials can be a dielectric, such as, silica including thermally grown SiO2 and chemical vapor deposited SiO2 using tetraethylorthosilane gas (TEOS). Further, advanced integrated circuits often employ low K dielectric materials.
In circuit fabrication, a series of deposition and etch steps is required to form a multi-level pattern on semiconductor wafer. A non-planar surface is created during these manufacturing processes, which can cause focusing problems for photolithography equipment. Poor focusing during lithographic alignment and registration results in low yield and decreased device performance.
A polishing method known as chemical-mechanical-polishing or planarization (CMP) is often used to polish a non-planar wafer during circuit fabrication. CMP processes can be used to planarize insulating layers, such as dielectric material, conductive metals and semiconductive layers by utilizing different polishing slurry and polish pad configurations. For example, CMP processes are used in multi-layer interconnection structures having overlying aluminum alloy layers to flatten the interlayer dielectric films. Also, CMP is required to form tungsten plugs and inlayed of interconnection structures. For higher speed integrated circuits, copper lines with low resistance are used in damascene structures. Due to the difficulty and high cost associated with dry etching copper alloys, trenches or damascene structures are dry etched into dielectric films and then filled with barrier layer followed by copper seed and electroplating of copper. Copper CMP is use to remove excess material above the inlaid trench.
Slurries used in copper CMP typically include an abrasive, an oxidizing agent, a complexing agent or ligand, a corrosion inhibitor, such as benzotriazole (BTA) and other compounds that act as protective film or act as surfactant. For slurries with a high concentration of BTA, a copper-BTA compound (Cu-BTA) is formed as chemical reaction by-product. Both abrasive-free and reactive liquid slurries used in copper CMP can generate insoluble residues during polishing, such as Cu-BTA complex compounds and other BTA-Cu-organic polymer complexes. At high copper removal rates or high copper dissolution rate, the copper ion concentration exceeds maximum solubility (Ksp). With a high concentration of available BTA, Cu(I)-BTA compounds precipitate from solution, and at high concentration, coagulate into a surface residue having the consistency of chewing gum. When a high concentration of polymer ligand is available, a Cu(II)-polymer complex can precipitate and coagulate with Cu-BTA to form an amorphous mixture or chain-terminated structure.
During polishing, the insoluble Cu-BTA residues stick to the surface of the pad and accumulate to the point of eventually filling the grooves in the polish pad. The accumulation of insoluble residue in the pad grooves and micro-pores disturbs the normal slurry flow pattern. Since the slurry flow pattern is especially disturbed in areas where the wafer contacts the polish pad, the residue adversely affects polishing uniformity. Also, the copper removal rate decreases as the residue builds up during polishing.
To combat the deleterious effects of the insoluble residues, manufacturers have attempted to mechanically remove the residues from the wafer surface by frictional contact with a polishing pad. As the residue film is removed, however, just as during copper polishing, the copper complex accumulates on the polishing pad and fills grooves in the pad surface. De-ionized water (DI-water) is normally used during pad conditioning to help lubricate the pad and to remove debris from the pad. A high-pressure DI-water spray is used to speed up the cleaning process in CMP machines equipped with a pressure sprayer. Due to insolubility of slurry by-products, however, DI-water is largely ineffective at cleaning the pads and even a high pressure DI water spray is ineffective in removing the sticky BTA-Cu-polymer complex.
Although, conventional diamond grid disks are widely used to remove debris from polishing pads, the disks only condition the surface of the pad and cannot remove the residue within the polish pad grooves. Also, brush conditioners simply disturb the residue within the grooves and are largely unable to condition the pad surface and remove the residue. Using conventional cleaners in combination with a condition brush can be effective at reducing the residue on the polishing pad, but this process requires long condition times, which reduces the overall throughput of the polisher. Also, due to the slow dissolution kinetics of Cu-BTA complex residue in conventional cleaners, the condition brushes become contaminated during the conditioning process. Further, even in-situ conditioning during polishing with a diamond conditioner disk does not efficiently remove the insoluble residues within the pad groove. Accordingly, a need existed for a cleaning solution that can effectively remove complex insoluble copper residues from wafer and polishing pad surfaces.

Rohm and Haas Electronic Materials CMP Holdings, Inc.


The present invention provides systems and methods for modeling the impact of a medium on the appearances of encompassed light sources using a Legendre polynomial series solution to a Radiative Transfer Equation for Spherical Media (RTE-SM) called an Atmospheric Point Spread Function (APSF). Using this APSF, it is possible to determine characteristics of the medium causing the multiple scattering of the light from the encompassed light source. For example, by observing a street light in bad weather at night, using the APSF, it is possible to determine whether the bad weather is haze, mist, fog, or rain. Similarly, the APSF may be used to estimate the size of particles in a liquid. It is also possible using the APSF to remove and/or add an effect of the medium on a light source captured in an image.

Arguably, nothing in the world impacts the daily lives of people more than the weather.
Perhaps nowhere is the effect of weather more strongly felt than on the runways of world's airports. Haze, mist, fog, and rain can and do prevent airplanes from being able to take off and land. Not only do these weather conditions present an inconvenience to travelers in the form travel delays, these conditions can be life threatening when fog, for example, makes it impossible for an airline pilot to see the runway. Naturally, such weather conditions also impact life in countless other ways as well.
Because of these effects, researchers have attempted to build machines and develop models that can accurately gauge the weather. For example, at many airports, visibility meters have been put in place for determining the visibility at discrete locations around the grounds of the airport. Such machines detect the impact of atmospheric conditions (such as fog) on a beam of light transmitted from a light source, such as a laser, to a detector. These machines rely on the principle that particles in the atmosphere scatter light incident on those particles. Such machines are problematic, however, in that they only sample light in a small region (e.g., a two foot by two foot region) and are based on single scattering. Moreover, because of the complexity of these machines, they are quite expensive.
In contrast to the single scattering principle used in these machines is the principle of multiple scattering. One easily understood illustration of multiple scattering is the manner in which bad weather impacts the appearance of light sources, especially when viewed at night. This impact is typically seen in the form of a glow or halo that appears to surround a light source. The appearance of this glow or halo is the result of light rays being deflected multiple times by particles in the atmosphere as they leave the light source, such that the rays appear to be originating from an area surrounding the light source.
Attempts have been made to model the effects of multiple scattering on light rays in the atmosphere. For example, one approach has been to assume that the paths of light traversal are random and then to apply numerical Monte-Carlo techniques for ray tracing. Monte-Carlo techniques are problematic, however, in that they attempt to predict the paths of light based upon each photon impacting each particle in the medium. Such an approach is highly dependent upon the specific properties of the medium, such as the density of the medium, type of particles in the medium, the size of the medium, etc. As a consequence of this, millions of rays must be traced through the atmosphere to accurately model the multiple scattering using Monte-Carlo techniques. Thus, when attempting to model a single light source in a single image, this technique can take several hours using current computer systems. Obviously, such a long processing time is inadequate for real-time or near-real-time image processing.
Monte-Carlo techniques are also problematic in that they do not converge for pure scattering media. This may be unacceptable when trying to model multiple scattering of certain media.
Another technique for modeling the impact of particles in the atmosphere on light is to use the plane parallel model. This model has been used in fields such as atmospheric optics and astronomy in which the medium being observed (e.g., the atmosphere around the earth) is illuminated by a distant light source such as the sun or moon. The plane parallel technique is problematic, however, in that it assumes that the light source is entering the medium from an infinitely far away distance, which is not the case when modeling the impact of an atmosphere on the appearance of a light source that is inside that atmosphere.
Accordingly, other techniques for modeling the multiple scattering of light from encompassed light sources and for using those models are desired.

Systems and methods for modeling the impact of a medium on the appearances of encompassed light sources

The Trustees of Columbia University in the City of New York


Base stations of a satellite navigation system have receivers Phase biases and instrumental and atmospheric errors, are determined and transmitted to navigation devices. Precise Point Positioning includes steps of: obtaining code and phase measurements which were performed on the satellite signals by the plurality of receivers at two or more frequencies, determining separate individual values for a plurality of phase ambiguities and a plurality of the errors based on the code and phase measurements, wherein the receivers are grouped into clusters, and in each cluster a determination of a single cluster solution is performed, in which satellite errors selected from the group of satellite position errors, satellite clock errors and satellite phase biases are determined based on the phase and code measurements performed by the receivers of the respective cluster; and a multi-cluster solution is performed, in which the single cluster solutions are adjusted.

Precise Point Positioning (PPP) is becoming attractive as the user does not need any raw measurements from a reference station. ZUMBERGE et al. [1] have introduced PPP using precise orbits and docks obtained from a large network of reference stations. KOUBA and HEROUX [2] describe PPP including a precise modeling of satellite antenna offsets, phase wind-up corrections, solid earth tides, ocean loading and earth rotation parameters. They have also assessed the performance using IGS (International GNSS Service) products. Precise satellite orbit and clock information can be obtained by the Bernese software as described by DACH et al. [3].
Precise knowledge of satellite phase biases is required for PPP with integer ambiguity fixing. GE et al. [4] used the Melboume Wübbena combination and the ionosphere-free phase combination. These combinations were applied to satellite-satellite single difference measurements of 450 IGS (International GNSS Service) stations to estimate the single-difference widelane biases and phase biases. The estimation is performed in two steps, i.e. a first step for the widelane ambiguity fixing, and a subsequent step for fixing the narrowlane ambiguities. The estimated phase biases of [4] vary by only 0.4 cycles per day for some GPS satellites. [4] also shows that their corrections enable a narrowlane (NL) integer ambiguity fixing, i.e. 91% of the float NL ambiguity estimates are deviating by at most 0.1 cycles from the nearest integer.
LAURICHESSE et al. [5] estimated undifferenced satellite phase clocks, station clocks, satellite differential code/phase bias, station differential code/phase biases, station coordinate corrections, satellite orbit corrections and ambiguities in a Kalman filter. They used the same combinations as [4], but processed undifferenced measurements. The assumptions on the process noise statistics are accurately described for each state parameter. [5] analyzed the evolution of the narrowlane pseudorange minus phase biases over the whole year 2008 for all GPS satellites. They distinguished between blocks IIA and IIR satellites and observed a drift of only 3 narrowlane cycles per year.
WEN et al. [6] proposed to estimate the undifferenced satellite phase biases, non-dispersive geometry correction terms including their time derivatives, slant ionospheric delays, and carrier phase ambiguities in a Kalman filter. The ambiguity fixing was triggered based on the stability of the float solution and the statistics of the Kalman filter. The method was applied to the regional network of SAPOS reference stations in Germany.
Carrier phase integer ambiguity fixing is essential for precise satellite phase bias estimates. BLEWITT et al. [7] proposed a sequential ambiguity fixing, which partially exploits the correlation between float ambiguities. The correlation was obtained from a triangular decomposition of the float ambiguity covariance matrix. TEUNISSEN [8] developed the famous Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) method to solve the integer least-squares problem. The LAMBDA method includes an integer decorrelation and a sequential tree search to find the integer ambiguities which minimize the sum of squared ambiguity residuals. TEUNISSEN [9] provides an expression for the success rate of integer bootstrapping based on the cumulative Gaussian distribution.
BRACK et al [10] proposed a sequential Best-Integer Equivariant (BIE) estimator for high-dimensional integer ambiguity fixing. The authors performed one-dimensional searches instead of one-dimensional search, which is much more efficient. The Sequential BIE was used for satellite phase bias estimation with 20 reference stations.
HENKEL et al. [11] developed an ambiguity transformation for GLONASS double difference carrier phase measurements to enable integer ambiguity fixing for FDMA-modulated signals. The transformation is used for joint ambiguity fixing of GPS and GLONASS.
LI et al. [12] discloses a multi-layer processing scheme for determining correction to be used for PPP. The scheme comprises four layers: In the first layer, precise satellites orbits are obtained by a network solution. The orbits from the first layer will be fixed for the precise clock estimation in the second layer. In the third and fourth layer, uncalibrated phase delays and ionospheric and tropospheric corrections are generated using the orbits and clock estimation derived from the previous layers.

Method for precise point positioning in a satellite navigation system


A self-retaining cementing wiper plug with a packer element has two or more steel or carbide tipped holddown fingers or slips extending radially outward from the plug for engaging the inner surface of the casing and preventing the plug from moving uphole over time and potentially interfering with other downhole apparatus such as a pump. The packer element in the wiper plug is actuated when the plug is supported by an obstruction under the plug and then compressed, the packer being maintained in compression by the holddown fingers.

It is conventional practice, in the drilling and completion of wells, to case an open hole by cementing tubular casing in place in a wellbore. Thus, the open hole is prevented from caving in, fragile formations are protected, inter-zonal communication is restricted and contamination of groundwater is prevented. In the course of cementing the casing, components are placed in the well which can later migrate and possibly interfere with well operations. To understand the phenomena, cementing operations are reviewed herein.
A string of casing is made up and lowered into the open wellbore. Prior to the placement of cement, the casing and hole are filled with drilling mud, which must be displaced for placing cement.
In the case of surface and intermediate casing, in order to reduce contamination of the interface between the displaced mud and the cement, a bottom cementing plug is placed in the casing and pumped ahead of the cement slurry. The bottom plug is typically constructed with a one piece hollow metallic or a one piece non-metallic core having an elastomeric covering molded to the core. The elastomeric cover typically incorporates a plurality of wipers. The function of the wipers is to wipe the internal surface of the casing, maintain the separation of fluids during the displacement of the cement slurry down the casing and provide a means of sealing upon displacement of the plug. The bottom plug incorporates a rupture diaphragm or valve that will rupture or open upon the bottom plug reaching or resting on a float shoe, float collar or landing collar located near or at the bottom of the casing. As a result, the bottom plug is supported and restrained from further downhole movement.
An increase in fluid pressure above the supported bottom plug results in the diaphragm rupturing, allowing the cement slurry to pass though the bottom plug and continue out the bottom of the casing, beginning to fill the annular space between the casing and the well bore.
When the necessary volume of cement has been placed into the casing, a top plug is positioned on top of the cement for separating the cement from a displacement fluid. The top plug is typically constructed having a solid elastomer, one piece metallic or one piece non-metallic core having an elastomeric covering molded to the core, the elastomeric cover incorporating a plurality of wipers.
Optionally, the top plug may also have a rupture element, as described in U.S. Pat. No. 5,191,932 and incorporated herein by reference in its entirety, so that if the top and bottom plugs are inadvertently reversed, in operation, cementing can continue without removal of the plug or removal of cement placed into the wellbore before the error was discovered.
Pressures required to rupture the diaphragm are such that the diaphragm will not rupture during normal operations. The function of the wipers is to wipe the internal surface of the casing, maintain the separation of fluid during the displacement of cement slurry down the casing using displacement fluid and to provide a method of providing a sealing mechanism across the casing upon landing the top plug on top of the bottom plug. When displacement of the cement slurry is complete, the top plug will land on top of the bottom plug and is expected to remain in this position once the cement hardens.
After the cement slurry has become hard, the top and bottom plugs are drilled out. Additional drilling of the wellbore can then proceed through the cemented casing. Additional lengths of casing are hung in the cemented casing and the cementing operation is repeated to cement the additional lengths of casing into place.
The last segment of casing to be positioned in the wellbore is the production casing. It is typically smaller in diameter than either the surface or intermediate casing and extends to the bottom of the wellbore. As no further drilling will occur after the production casing has been run in and cemented, the plugs are not drilled out, but instead are left cemented into the bottom of the hole. As with the previous cementing operations, a bottom plug is run ahead of the cement and a top plug is run behind. Once the top plug rests on the bottom plug, pressure sufficient to keep the plugs at the bottom of the hole, but not to rupture the diaphragm in the top plug, if present, is maintained on the plugs for approximately 8 hours to permit the cement to properly set.
Once the wellbore has been cased, the casing is perforated above the plugs at a zone of interest and the wellbore is ready for production. A tubing string and pump are lowered into the casing and fluids are produced up the tubing string to surface.
Applicant is aware that in many cases, often a year or more after the cementing of the casing, the top cementing plug can migrate up the production casing to the pump intake and cause fouling of the pump. Typically, most wellbores have a minimum overhole, that is to say, the bottom of the casing is not far below the zone to be perforated. Applicants believe that during perforation of the casing, the cement surrounding the plugs and outside the casing may be fractured. If sufficient fracturing occurs, the plugs are no longer held securely inside the casing and can migrate upwards. It is also possible that gas from the formation can travel downward through the fractured cement outside the casing and rise at the bottom of the casing to apply pressure on the plugs. If one-way valves in the float equipment are also damaged as a result of pressure pulses during perforation, are washed out during cementing or have material trapped therein, against a seat, preventing closure, then the plugs may be forced upwards due to the increased pressure from below.
Traditionally, whenever the pump intakes are fouled, production is lost and the tubing is tripped out of the well to repair the pump, at great expense. A solution that has been employed to prevent plugs from migrating upwards into the pump intake is to run a bridge plug into the casing and set it down on the top cementing plug to anchor the plug in position. Whether repairing the pump or setting a bridge plug, significant expense is involved in both equipment and rig time.
Applicant, in corresponding U.S. application Ser. No. 10/640,056, filed Aug. 14, 2003 and claiming foreign priority benefits of Canadian Patent Application 2,406,748, filed Oct. 3, 2002, both of which are entitled SELF-ANCHORING CEMENTING WIPER PLUG, the entirety of which are incorporated herein by reference, describes a self-retaining cementing wiper plug which solves the problems related to migration using two or more holddown fingers biased radially therefrom and extending outward for engaging an inner surface of the casing once the plug is positioned at the bottom of the casing. Substantially, regardless of the formation, the novel plug is prevented from migration. The holddown fingers are angled uphole, as are the wipers, to enable insertion into the casing bore and are flexible relative to the plug only in so much as the elastomeric body in which they are embedded flexes or the attachment to the core of the plug permits limited flex, to permit insertion. The fingers themselves are substantially inflexible so as to resist flexing once engaged with the casing to prevent movement of the plug uphole.
It is important to note that a wiper plug is designed to prevent fluid flow downhole past the plug and can permit uphole flow. However, when used as a top wiper plug, differential pressure across the plug can cause fluids to flow from a lower zone which is undesirable once the top wiper plug has been set.
Regardless of the reason or hypothesis for plug migration, clearly there is a need for means to prevent the cementing plug from migrating up the casing. Ideally, such means would be incorporated directly into the plug, thus realizing significant cost and time savings and further, there is a need for a device for blocking uphole fluid flow once the top plug is in place.


Even when a same C-RNTI is allocated to multiple mobile stations in a phantom cell, a collision between the mobile stations UE to which the same C-RNTI is allocated is avoided. A radio base station PhNB#10 according to the present invention is configured to manage a cell #10 (phantom cell) which is formed by linking multiple small cells and includes an allocation unit 11 configured to allocate a same C-RNTIph to multiple mobile stations UE#1/UE#3 which are separated by at least a predetermined distance in the cell #10.

In LTE (Long Term Evolution), a radio base station eNB is configured to transmit/receive data to and from a mobile station UE performing communications in a cell under the control thereof, with a C-RNTI (Cell-Radio Network Temporary Identifier) allocated to the mobile station UE as illustrated in FIG. 4 (see, Non-patent document 1).
The C-RNTI is allocated on a cell-by-cell basis. In LTE, as illustrated in FIG. 4, a same C-RNTI cannot be allocated to a mobile station UE#1 and a mobile station UE#2 which perform communications in a same cell #A, and a same C-RNTI can be allocated to a mobile station UE#1 (or a mobile station UE#2) and a mobile station UE#3 which perform communications in different cells #A/#B.
Here, the C-RNTI is allocated in "Contention based RA (Random Access) Procedure" or a handover procedure.
In addition, the radio base station eNB is configured to allocate resources for transmitting downlink data and uplink data by using the C-RNTI allocated to the mobile station UE.
Meanwhile, in the "Rel-12 workshop" of the 3GPP, many proposals on "Small cell enhancement" have been made as a topic of FRA (Future Radio Access).
In such proposals, a concept of "Phantom cell" has been discussed.
As illustrated in FIG. 5, unlike a conventional macro cell, a phantom cell can cover a wider area by linking many "small cells" to form one large cell.


An inventive isolated converter which exempts the auxiliary isolation devices with accurate voltage regulation is disclosed. The converter includes the primary side circuit with a primary controller controlling the on and off of the primary switch and a secondary side circuit with a secondary controller controlling the on and off of the secondary synchronous rectifier. The isolated converter uses the secondary controller to turn on the secondary synchronous rectifier after the secondary current decreases to zero to generate a negative tail current and turns off the secondary synchronous rectifier at a reference tail current peak value to generate a reflected negative current at the primary side circuit for turning on the primary switch.

Isolated converters are widely used in situations with high safety requirements and off-line power supply. A control is desired with high accuracy, high efficiency, low EMI, small size and low cost. Feedback control is essential to accurately adjust the energy delivered to the load. For isolated converters, a basic requirement of feedback is electrical isolation between the primary side and secondary side.
An optical coupler is commonly used in feedback control to achieve electrical isolation. The output voltage information at the secondary side is fed back to the primary side through the optical coupler to accurately control the primary side switch delivering the optimal energy to the secondary side. One drawback of employing an optical coupler is that it increases the system cost. Further, an optical coupler can be damaged under high isolation voltages. For example, in medical instrumentation applications, power supply systems require high reliability and often suffer from high voltage spikes.
Another isolated feedback approach uses a dedicated third winding or auxiliary winding. The output voltage at the secondary side is similar to that in the auxiliary winding. Thus, by detecting the voltage at the auxiliary winding side, feedback information can be obtained. However, there exist problems while adopting the feedback approach. One problem is that it can not accurately reflect the output level, especially during a load transient. Like the optical coupler, the auxiliary winding approach increases cost. Thus, it is a challenge to realize the voltage feedback control accurately in a simple way.
Besides cost and accuracy considerations, high efficiency and low EMI are also desired. One approach is using soft switching technology such as ZVS (zero voltage switching) to reduce the switching loss. For ZVS, the drain-source voltage of the switch is zero when the switch is turned on so that there is no turn-on loss. Also, a snubber capacitor can be paralleled directly with the power MOSFET. The dv/dt is greatly reduced, which not only lowers the turn-off loss, but also reduces EMI significantly. With the reduction of the switching loss, the converter can run at higher switching frequency, which reduces the sizes of transformer and other passive components.
The quasi-resonant converter is a typical isolated converter with soft switching and feedback control. FIG. 1 shows a prior art topology of a quasi-resonant converter wherein Lp is the inductance of the primary winding, Rp is the resistance of the primary winding, Cp is the resonant capacitor, and Ld is the inductance of the auxiliary winding. When the energy at the secondary side depletes (magnetic flux resetting), there is an oscillating voltage at the drain of the primary switch Qp. The resonant frequency is determined by Lp and Cp, and the attenuation factor is decided by Rp. An auxiliary winding Ld is employed to detect the magnetic flux resetting and thus control Qp turn-on at the bottom of the oscillating voltage to decrease the switching loss. Meanwhile, an optical coupler is used to feedback the output voltage information to the primary side to regulate the energy delivered to the secondary side. As described above, the quasi-resonant converter adopts both the auxiliary winding and an optical coupler to realize feedback and soft switching. However, it can not ensure a zero voltage switching and it has large size and high cost.

Tail current control of isolated converter and apparatus thereof


A health check mechanism for an overlay network may employ tunneling technology. A health check packet may be sent between endpoints. The health check packet may be recognized in the network and may initiate a health check process on receipt. In some embodiments, the health check packet may include a signature recognized by the network. A destination endpoint, upon receipt of the health check packet, may provide health check statistics to a source endpoint.

The present invention relates to network maintenance, and more specifically, to a tunnel health check mechanism in an overlay network.
In some networks non-connection oriented tunnels may be employed to transport data between endpoints. This may be primarily due to the large number of endpoint pairs and the high cost of maintaining connection information which could be cost prohibitive. However, because only endpoints may be able to read data packets, it may be unknown whether traffic from a source is reaching the destination. Thus, it can be seen that employing a health check mechanism may be beneficial toward ensuring the operating efficiency of an overlay network.

Tunnel health check mechanism in overlay network

INTERNATIONAL BUSINESS MACHINES CORPORATION