A method of treating cleaning solvent used to clean mechanical parts. The method includes adding to the cleaning solvent a treating composition selected from the group of C.sub.5 -C.sub.14 alcohols, C.sub.2 -C.sub.8 dials, C.sub.10 -C.sub.14 polyols, and C.sub.4 -C.sub.14 glycol ethers, and mixtures thereof. A further embodiment includes the foregoing plus adding a clarifying agent from the group of aromatic, aliphatic and alkaryl sulfonic acids and sulfonic acid salts, esterified polyols, and alkyl phenol formaldehyde resins capped with alkoxy groups. The solvent is vaporized and condensed to effect recycling thereof without adding substituted quantities of treating composition to the solvent.

The present invention relates generally to automotive, industrial, and commercial parts cleaning, and, more particularly, to improved formulations for increasing the effectiveness and recyclability of cleaning solvents.
In industry today, there has been an increasing awareness of the importance of washing mechanical parts. In almost every repair, reconstruction, and rebuilding of motors, engines, and/or machines, it is necessary to clean oily, greasy, or otherwise dirty or contaminated parts before they can be repaired and reassembled. Further, in a number of cases, machining and refabricating operations, particularly those carried out on metal parts, leave residues or contaminants which are desirably cleaned before the part or component in question is reassembled or otherwise the subject of a completed operation.
In most cases, the kind of dirt and contamination which has accumulated on metal parts is that of an oily, greasy residue. In the case of automotive, truck, agricultural, and earth-moving construction machinery components, the parts in question gradually become covered with oil or grease that has leaked from the crankcases or gear housings of the machines, and these in turn attract dust, sand, dirt, and other constituents of the environment in which they work. Almost all oils and greases have the capability not only of attracting dust and dirt, but also, in effect, of acting as an adhesive for these and other contaminants.
Normally, for reasons of rust prevention, and particularly for reasons of solubility, such parts, being possessed of an oily, greasy residue, are best cleaned using hydrocarbon-based solvent systems rather than aqueous systems. The use of aqueous systems calls for using large quantities of water and requires emulsifying the oil and grease that is, in effect, serving as a dirt binder. Such cleaning, while effective if conducted properly, involves time-consuming washing/emulsification/saponification steps followed by rinsing and subsequent application of a corrosion inhibitor coating. In addition, disposing of oil-containing residues is sometimes subject to prohibition or regulation.
Accordingly, rather than pursue this method, most parts are simply washed in a hydrocarbon-based solvent that is compatible with the oils and greases in question, and which therefore serves to remove the dirt quite rapidly and effectively. This is particularly true when combined with a scrubbing or mechanical agitation action, i.e., brushing or dipping and agitating of parts, or both. Where the solvent is confined to a recirculating washer, the solvent can be retained and collected for recycling so as not to require being disposed of in violation of environmental regulations.
In connection with the use of hydrocarbon-based solvents, certain problems arise. These include environmental and fire hazard concerns, one consequence of which has been the increasing use of relatively high flash point solvents. In many cases, these solvents used have a flash point of 100.degree. F. or above and are primarily aliphatic in nature with a certain aromatic constituent. Newer solvents have a 150.degree. F. or higher flash point and are predominantly or almost exclusively aliphatic.
Referring to the equipment used in parts washing, while simple dip tanks have been known to be used with some effectiveness, the most cost- and labor-effective method of small-scale parts washing, (i.e., that carried on in maintenance, repair, and rebuild shops and garages and industrial fabrication and assembly facilities of all sizes), has been to use parts washers which include a sink or the like positioned atop a reservoir of hydrocarbon-based solvent and wherein this solvent is circulated from the reservoir though a pump and directed over the parts being cleaned from a nozzle at the end of a conduit or the like. Parts washers using such hydrocarbon-based solvents include those of the general type described in U.S. Pat. No. 3,522,814, of which many hundreds of thousands have been sold and/or are in use.
Referring again to automotive, industrial, and commercial parts washing, when the cost of hydrocarbon-based solvent was very low and the regulatory atmosphere was somewhat lax, it was not uncommon to provide a rather crude filter to be used with such solvent and for the solvent to be changed by a route or serviceman every two to four weeks. The used solvent would be picked up by the route man, who then furnished a charge of new solvent for the parts washer. This cycle would commonly be repeated on a two to twelve week cycle or as needed.
When hydrocarbon-based solvent prices were low, this was an economical, common sense approach to parts washing problems. The combination of the relatively crude filter and simple gravity settling provided a gross separation of contaminants which was satisfactory for the times in question. Now, however, hydrocarbon-based solvent costs are much higher, and environmental regulations are such that it is much more desirable to ensure maximum use and re-use of a particular charge of solvent. However, this desirable state of affairs has not heretofore been able to be fully achieved in practice.
One characteristic of parts washer solvent that has been subjected to even comparatively few washing cycles is that the dirt entrained therein includes finely dispersed particles, many of which may be of sub-micron size. While sand, gravel, metal filings, and the like cleaned from dirty or greasy parts rapidly settle out, a significant portion of the contaminants in solvent used for parts washing is comprised of very fine particles that are resistant to settling. As a result, while the solvent's cleaning effectiveness may not be impaired, due to the dispersed and unsettled contamination, it may be difficult to determine visually that the solvent can still be used effectively. Consequently, such solvent may be changed more often than needed.
If it were possible to achieve a greater separation of dirt and particles from the mass of solvent within a finite time, say fifteen minutes to one hour, the effectiveness and useful lifetime of much parts cleaning solvent would be greatly increased. It is possible that, by positioning the liquid pump inlet an appropriate distance from the bottom of the reservoir, if there were highly effective gravity separation of contaminants, the pump could continue to circulate comparatively clean solvent, while the case, the contaminants would continue to self-separate by gravity. Thus, the supernatant liquid within the reservoir would remain clean and be able to be used over a much longer period of time.
In speaking of reclamation of hydrocarbon solvents, being that the current regulatory atmosphere in some ways promotes this practice, when recycling of the hydrocarbon-based solvent used in parts cleaning is called for, i.e., by filtration, distillation of the solvent at a recycle center, and/or by various other commonly known methods, an economic price is extracted both for recycling very dirty solvent and also for distilling solvent that has sufficient solids suspended so as to be of reduced effectiveness in use as a cleaning material.
If it were the case that a greater separation of the dirt and particles in used or spent hydrocarbon-based solvent could be achieved, recycling would be simplified in that the major portion of the contaminants could be removed into a contaminant-rich layer by physical separation, thus reducing the accumulation of sludge in the distillation phase of recycling. Heat transfer would be better and equipment damage would be minimized if the solvent that was ultimately recycled by distillation were cleaner when entering the distillation phase of recycling.
While it is not known with certainty all the reasons why the contaminants in parts cleaning hydrocarbon-based solvent are apparently so highly resistant to gravity separation, it is known that modern motor oil, cutting and machining fluids, and grease formulations include detergent/dispersant additives which form a part of the dirt and grime which accumulates on mechanical parts, both inside and outside sealed machine areas. The detergent/dispersant additives remaining in these oil, fluid, and grease residues may serve to suspend fine contaminants within the cleaning solvent and prevent their separation by gravity or filtration.
A drawback with the concept of adding certain performance enhancing products to solvent for the purpose of separating therefrom suspended, fine-particle-size contaminants has been that of expense of the additive. Hence, since the main incentive to clarify solvents used in parts washing application is to economize on the use of solvent, primarily by creating particle separation that enables the supernatant layer of the solvent to be used for longer periods of time, if such a process involves considerable effort and expense, then it cannot be economically justified.
Moreover, if any treatment is such that it renders ineffective a primary requirement of the solvent, namely, that it be able to be recycled, then such additives or modifying compositions would be seriously disadvantageous. Accordingly, if a relatively persistent additive were able to be found, such an additive would have economic advantages in that it would be able to be used for a significant period of time.
Moreover, if an additive available which would not only be persistent in use, but which would remain in a solvent composition to and through a recycling phase, then such a composition would have an extremely important economic and ecological advantages.
In view of the inability of the prior art to have developed an additive composition for a cleaning solvent, particularly a parts washing solvent, which additive would be highly persistent in use, and might even survive recycling by distillation, an object of the present invention is to provide an improved petroleum or other solvent composition that includes a durable or persistent component that also aids contaminant particle separation.
A further object of the invention is to provide a solvent which will provide a combination of properties, namely, the ability to impart rapid agglomeration of dispersed fine particles in the solvent and which would survive recycling by distillation.
A further object of the invention to provide an enhanced solvent that greatly accelerates dirt and particle separation and remains effective after solvent reclamation and/or solvent recycling has been conducted by various methods, including distillation.
A still further object of the invention is to provide an enhanced solvent and/or solvent additive that facilitates easier initial separation of contaminants for more efficient and cost effective recycling, especially wherein the additive largely remains in a solvent supernatant layer rather than separately with agglomerated contaminants.
Another object of the invention is to provide a modified composition wherein a single additive, or combination of related additives, will serve to perform a solvent clarifying function in respect to fine particles and which additive will further remain present in the solvent during repeated distillative recycling.
Yet another object of the present invention is to provide a composition which, when added to a cleaning solvent, is compatible with other additives such as settling accelerants, as well as with impurities or other contaminants finding their way into parts washing solvent.
Another object of the invention is to provide a persistent additive for a solvent, which additive is effective in the presence of certain limited amounts of water and whose performance in some cases is enhanced by the presence of small portions of water.
A further object of the invention is to provide a composition which will form an azeotrope or constant boiling mixture with a range of solvent compositions so as to remain with solvent being distilled rather than being separated therefrom by distillation.
Yet another object is to provide a method of providing improved solvent performance, which method comprises treating cleaning solvent with an additive which will extend its service life, thereafter distilling the solvent after use to separate therefrom high boiling residues, and repeating this process periodically, occasionally adding a slight additional amount of the additive sufficient to return the solvent composition to its original specification.
Another object of the invention is to provide an additive which is compatible with and not harmful to equipment used in distillative recycling.
The foregoing and other advantages of the invention are achieved in practice by providing a solvent processing method which comprises adding to a body of solvent a treating composition comprising an active ingredient selected from the group consisting of C.sub.14 and lower alcohols, C.sub.14 and lower diols, C.sub.14 and lower polyols, C.sub.14 and lower glycol ethers, and mixtures of said alcohols, diols, polyols and glycol ethers, preferably of the C.sub.6 -C.sub.8 variety, utilizing the solvent in a parts washing operation and periodically distilling the same to remove impurities, and, following distillation, determining the effective level of such additive in the composition, and periodically adding small amounts of said composition until the solvent composition has reached its original specification.
The manner which the foregoing objects and advantages of the invention are achieved in practice will become more clearly apparent when reference is made to the preferred manner of practicing the invention, as reflected in the examples set out below.


A communications manager in a telecommunications transaction server communicates service request messages and service response messages between one or more remotely executing service request processes and one or more service applications executing on the transaction server. A main thread in the communications manager monitors connections requests and initializes other threads. A unique logical communications connection is established between one of the service request processes and the communications manager. The communications manager creates both a read thread and a write thread for each logical communication connection that is validated and active. The read thread communicates service request messages from a service request process to an appropriate service application. The write thread communications service response messages from the service application to the service request process that issues the service request message. A monitor thread collects service response messages from a queue and directs them to the appropriate write threads via an in-memory write queue.

1. Field of the Invention
This invention relates in general to communications systems, and more particularly to providing a real-time message routing communications manager in a communications system.
2. Description of Related Art
Modern telecommunications network carriers ("carriers") typically provide a broad range of telecommunications services, such as 1-800 services, Virtual Private Network (VPN) services, and Calling Card (CC) services. Computing platforms, generally called Service Control Points (SCPs), are used for real-time processing of such services.
For example, a customer may contract with a carrier to provide a 1-800 service with intelligent call routing. When the 1-800 number is dialed by a caller, a 1-800 service request is sent across a telecommunications network to an SCP. A 1-800 service application executing at the SCP receives the service request and determines the proper call center to which the call should be routed, in accordance with routing parameters provided by the customer (e.g., time of day, call center volume, geographical origin of the call). A service response indicating the proper routing of the call is then returned through the telecommunications network to connect the 1-800 call with the proper call center. It is desirable that the service processing be transparent to the caller, maintaining real-time performance to connect the call.
Typically, an SCP is coupled to a telecommunications network via a telecommunications switch and includes one or more client server communications managers (CSCM) and one or more transaction servers. A CSCM interfaces between the switch and the transaction server, providing functions such as protocol conversion and allocation of service requests among multiple transactions servers (e.g. load balancing). A transaction server executes the service applications that provide services to the telecommunication network. Service requests, such as a 1-800 service request, are received through the switch by one of the CSCMs and sent to one of the transaction servers for processing by a service application. Optimizing the communication of messages (e.g., service requests and responses) among the CSCMs and the transaction servers is an important factor in maintaining real-time performance.
Traditionally, proprietary communication systems and communication methods have been employed to communicate among communications managers and transaction managers. However, open computer systems have gained popularity largely because customers wanted choices among multiple computer vendors to solve their computing needs. The growing use of distributed systems has given rise to a need to develop applications capable of running in an open environment while executing on a variety of different computing systems. Accordingly, proprietary communications methods are being replaced by solutions supporting open, published, and widely-available communications standards, such as TCP/IP (Transmission Control Protocol/Internet Protocol), which is not specifically designed to provide real-time communications. For example, although the TCP protocol guarantees message delivery, there is no inherent mechanism for guaranteeing that a read or write on a single connection does not impact (i.e., decrease) the communications performance of other communications on that connection or on other connections. As such, a specialized communications application is needed to maintain real-time performance of calls involving telecommunication services in an open system environment.

Method and apparatus for providing a real-time message routing communications manager


This invention relates to methods for preparing cyclic peptides and peptidomimetic compounds in solution and bound to solid supports, and to cyclic peptide or peptidomimetic libraries for use in drug screening programmes. In particular, the invention relates to a generic strategy for synthesis of cyclic peptides or peptidomimetics that enables the efficient synthesis under mild conditions of a wide variety of desired compounds. Two approaches were evaluated for their improvements in solution and solid phase synthesis of small cyclic peptides: positioning reversible N-amide substituents in the sequence; and applying native ligation chemistry in an intramolecular sense. Systematic investigation of the effects of preorganizing peptides prior to cyclisation by using peptide cyclisation auxiliaries, and developing new linkers and peptide cyclisation auxiliaries to aid cyclic peptide synthesis gives surprising improvements in both yields and purity of products compared to the prior art methods. The combination of these technologies provides a powerful generic approach for the solution and solid phase synthesis of small cyclic peptides. The ring contraction and N-amide substitution technology of the invention provide improved methods for the synthesis of cyclic peptides and peptidomimetics. When used in conjunction with linker strategies, this combination provides solid-phase avenues to cyclic peptides and peptidomimetics.

Amide bond formation is one of the most studied reactions in chemistry and biology. It allows peptide and protein synthesis, and enables the synthesis of peptide-like molecules, known as peptidomimetic compounds, which are widely used in drug design and discovery programs. A plethora of reagents and reaction conditions have been developed over the years that facilitate amide bond formation by activating a carboxylic acid and mixing it with a primary or secondary amine. In a number of cases however the acylation reaction may not go to completion or may not proceed at all. Despite the progress and extensive research efforts in this field, so-called "difficult" amide bonds still exist that prevent access to a large number of compounds of great interest to the research community. In particular these include small cyclic peptides, large peptides and proteins and difficult peptide sequences. In these cases, attempts to force the acylation by heating or by increasing the activity of the activated ester result in undesirable side reactions, such as racemisation, or dimerisation. In these cases a different approach is required to facilitate the amide bond formation. In the past 10 years a number of auxiliary strategies have been developed that make use of an intramolecular acyl transfer to overcome some of these problems. These strategies and their targets are outlined in more detail below.
1. Native Ligation Chemistry
The general idea of chemical ligation is to synthesise large proteins in high purity. The process capitalises on the ability to generate highly homogeneous linear peptides of up to 50 residues long by using optimised solid phase peptide synthesis. These peptide segments are then linked or ligated in solution, using mutually reactive entities at the end of each segment. The major limitation to the existing ligation strategies is that they only work for a very limited number of ligation sites.
Several examples have been published where mutually reactive groups generate an amide isostere. In these first examples the ligation chemistry produced a modification in the peptide backbone of the product. In 1986, Kemp et al (1986) proposed a thiol-capture strategy, which is illustrated in Scheme 1.

Here two peptide segments are ligated using a mercaptobenzofuran substituent at the C-terminus of the first segment. The second segment, carrying a cysteine residue at the N-terminus, reacts to form a disulfide link. Following an O-to-N-acyl shift the disulfide link is cleaved, generating a "native" amide bond. This auxiliary strategy, although revolutionary in its own right, lacks versatility and has only been used successfully in a very limited number of cases (Fotouhi et al, 1989) due to the inherent difficulties in synthesising the selectively-protected peptide segments. It differs from our invention in the strategic approach and the design of the auxiliary. The same group has studied a number of parameters that influence the rate of the intramolecular acyl transfer, mostly focussing on the shape of the auxiliary (Kemp et al, 1981). This work is very different from our invention, and in no way suggested anything that is described in this invention.
In 1994 Dawson et al (1994) introduced the concept of native ligation, which allows the generation of proteins with a native or unmodified backbone from fully unprotected building blocks. This approach, outlined in Scheme 2, uses chemistry first described by Wieland for reacting amino acids.

In a first step an unprotected peptide-α-thioester selectively reacts with the thiol functionality on the N-terminal cysteine side chain of a second unprotected peptide. The initially-formed thioester undergoes a spontaneous acyl transfer in the aqueous buffer from a sulfur to a nitrogen atom, thereby generating a standard peptide bond. Several examples illustrate the significance of this work in enabling the synthesis of large proteins in high purity (Hackeng et al, 1997). One of the limitations of this native ligation strategy is that it relies on the presence of a cysteine residue somewhere in the middle of the target peptide sequence.
In an extension of this work, Canne et al (1996) reported a native ligation strategy that uses an auxiliary at the N-terminus of one of the peptide segments. The strategy avoids the necessity for an N-terminal cysteine residue, and expands the range of sites amenable to native chemical ligation to X-Gly and Gly-X. The strategy is outlined in Scheme 3.

A peptide-α-thioester reacts with an Nα (oxyethanethiol) peptide to produce the ligated product. The thioester-linked intermediate rearranges via an acyl transfer to an amide-linked product. The N—O bond at the tertiary amide can be readily cleaved using zinc dust in acidic aqueous solution, thereby releasing the oxyethanethiol auxiliary and producing the native backbone structure in the ligated product. The scope and limitation of this auxiliary approach was examined by selecting a range of different ligation sites.
It was found that the S-to-N acyl transfer only proceeded well for Gly-Gly ligation sites, but was more difficult when steric hindrance around the ligation site was increased. For example, in the case of a Gly-Ala ligation site the rearrangement, was incomplete after 10 hours in the pH 7.5 buffer. Lowering the pH to 4.5 accelerated the rearrangement, which was complete after 10 hours. In the case of a Phe-Gly ligation site rearrangement was almost complete after 2 days at 37° C. For the more hindered Phe-Ala ligation site no S-to-N acyl transfer step was observed, even after lowering the pH or leaving the sample at 37° C. for 24 hours. It was thus concluded that only Gly-X or X-Gly ligation sites will produce the target product. The limitation lies in the acyl-transfer step, which does not proceed for hindered ligation sites. The strategy differs from our invention in the way the auxiliary is introduced and removed, and in the design of the auxiliary.
Native ligations have also been performed using resin-bound peptides. One such strategy (Camarero et al, 1998) involves the assembly of a first peptide segment linked via a C-terminal thioester to the solid support, then adding the second segment containing a cysteine residue at the N-terminus, and performing the native ligation steps as for solution phase ligation. This has the advantage that handling of the intermediates is significantly reduced. Furthermore, several ligations can be performed in series using the same chemical approach. The limitations for the solid phase approaches are the same as for the solution phase chemistry, ie native ligation can only be performed at X-Cys, Gly-X or X-Gly sites.
2. Small Cyclic Peptides
Proteins and peptides are the primary means of initiating biological processes by interacting with macromolecular receptors. The crucial information determining the specific activity is often contained in relatively small sequences at the surface, and is determined by the three-dimensional conformation in which that sequence positions its side chains when interacting with the receptor. In the linear form, bioactive peptides can assume millions of different conformations, only very few of which are able to bind to the target receptor. In order to assess the important structural and dynamic properties that are critical to the biological potency and selectivity, conformational constraints are introduced, typically through cyclisation. Such cyclic molecules exist in more defined conformations, and are therefore very appealing from the point of view of pharmaceutical lead discovery. If activity is maintained or enhanced in these cyclic peptides, structural information is obtained, for example by NMR, X-ray or molecular modelling, and used to guide the development of therapeutic drugs. In addition, cyclisation generally promotes an increase of metabolic stability and bioavailability of peptides.
As the side chains are considered the main mediators for receptor interaction, cyclisation is preferably accomplished between the C- and N-termini. Whereas the synthesis of linear peptides generally proceeds well, head-to-tail cyclisation is often troublesome. This is particularly so for small peptides, ie. those less than seven residues long. All-L cyclic tetrapeptides for instance are not very accessible (Schmidt and Langner, 1997). The primary reason for ineffective cyclisation originates from what are called "difficult sequences". In cyclisation terms this refers to a sequence-related inefficiency in "bringing the ends together" for head-to-tail cyclisation. Peptide bonds have strong π-character, and preferentially adopt a trans conformation. Linear precursors are therefore generally extended in conformation with terminal carboxylic acid and amine functional groups in remote positions, and are thus unfavourable for cyclisation. The problem is most prominent in the synthesis of small cyclic peptides, where activation of the C-terminus often results in the formation of linear and cyclic dimers or oligomers with low or no yield of target cyclic monomer.
There have been very few studies that address the "difficult" cyclisation issue. Cavalier-Frontin et al (1993) reported on the use of reversible chemical modifications of the peptide backbone to enhance cis-amide conformations. In the synthesis of cyclo-[Phe-Phe-Phe-Phe] (SEQ ID NO:32), each amide N was substituted with a BOC protecting group. The cyclisation yield increased from 1% to 27%. Similarly, the use of the N-(2-hydroxy-4-methoxybenzyl) (Hmb) group as a reversible N-backbone amide substituent has resulted in increases in yield of cyclic peptides (Ehrlich et al, 1996). It must be emphasised that here the "auxiliary" is placed on the backbone amide, and not on the N-terminal amine that reacts to form the "difficult" amide bond.
In the past two to three years a few studies where ligation chemistry was used in an intramolecular fashion have been reported. In these examples an initially larger ring is formed, and ring contraction accomplished through an intramolecular O-to-N or S-to-N acyl transfer.
In a first method reported by Botti et al (1996), linear unprotected peptides carrying a cysteine residue at the N-terminus and an aldehyde at the C-terminus, were cyclised to generate a thiazolidine containing cyclic peptide, as shown in Scheme 4. Initially a larger cycle is formed, in which the C- and N-termini are prepositioned for O-to-N acyl transfer and ring contraction to a smaller cycle. The disadvantage of this method is that the cyclic product always contains a thiazolidine moiety in the cycle, with an additional chiral centre which results in the formation of two diastereomers, and requires a cysteine residue at the N-terminus of the linear precursor. The method does not allow the generation of unmodified cyclic peptides, and is not a versatile procedure suitable for a combinatorial library approach.

Muir et al demonstrated that "native" ligation, using a cysteine residue at the N-terminus and a thioester at the C-terminus, can be applied in an intramolecular way to generate cyclic peptides (Camarero and Muir, 1997), as shown in Scheme 5. In Scheme 5, YAVTGRGDSPAASS is SEQ ID NO:33 and cyclo-CYAVTGRGDSPAASSG is SEQ ID NO:34.

A 15-residue unprotected peptide containing a C-terminal thioacid was converted to the head-to-tail cyclic peptide by dissolving the activated Cα-thioester in a pH 7.5 buffer. Cyclisation was complete in 10 minutes. The initially formed cyclic thioester rearranges quickly to form the final peptide bond. The strategy is not generic, as it requires a cysteine residue at the N-terminus.
In a similar way Shao et al (1998) showed that N-(oxyethanethiol)-glycine at the N-terminus can be employed to achieve cyclisation by allowing the thiol functionality to react regioselectively with a thioester at the C-terminus. These strategies, as the authors point out, are limited by the types of residues involved at the C- and N-termini. Cyclisation is only possible between Gly-X, where X is a non β-substituted residue. The slow acyl transfer is again the limiting factor in this cyclisation strategy.
None of these methods provides a versatile synthetic route to enable synthesis of cyclic peptides with unmodified or native peptide backbone. The first two methods require the presence of cysteine at the N-terminus and the last lacks versatility, as the ring contraction only proceeds for non-hindered cases. We have found that the latter approach does not provide access to a number of known "difficult" cyclic peptides.
3. Backbone Substitution
One of the major problems in solid phase peptide synthesis (SPPS) is the inefficient assembly of the so-called "difficult" sequences. Moreover, these sequence-related difficulties are impossible to predict a priori. The problems are believed to be mainly due to inter- and intra-chain aggregation during the assembly of the protected peptide on the solid support. This has led to the development of the backbone substitution strategy (Hyde et al, 1994) outlined below in Scheme 6. A 2-hydroxy-4-methoxybenzyl substituent (=Hmb) is introduced by using N,O-bis-Fmoc-protected (Hmb)-amino acids. In general acylation of N-substituted amino acids other than glycine requires forcing conditions, due to the massive steric hindrance imposed by the N-substituent. In the case of the Hmb-substituted amino acids, acylation is substantially enhanced through an internal acyl transfer mechanism. Acylation initially occurs on the phenolic oxygen atom, enabled by the intramolecular presence of an amine base, and is followed by an acyl transfer from the oxygen to the nitrogen atom. Fmoc-solid phase synthesis then proceeds, with significantly improved yields for peptide sequences that are difficult to assemble using standard SPPS.

After assembly the peptide is deprotected and cleaved using TFA, with concurrent removal of the Hmb backbone substituent yielding target unprotected peptide in high yields and purity. This backbone protection can also be employed to prevent aspartimide formation, and to improve solubility of protected peptides. In a recent report Hmb groups were introduced on resin-bound peptide via reductive amination, thereby avoiding the use of the more tedious N,O-bis-Fmoc (Hmb)amino acids (Nicolas et al., 1997).
There are two major limitations in the Hmb-backbone protection strategy. Firstly the internal O-to-N acyl transfer only proceeds well for non-hindered cases. When a β-branched amino acid has to be coupled to a Nα-Hmb residue other than glycine several hours of heating (80° C.) is required for the rearrangement to proceed. Secondly, this group is only compatible with Fmoc chemistry, and not with the often-preferred BOC SPPS, due to its TFA lability.
The Hmb methodology has demonstrated that backbone substitution can alleviate sequence related assembly problems for Fmoc chemistry. However, for hindered cases it creates additional problems of its own. The methodology would benefit significantly from the development of a more acid stable auxiliary that would allow a faster intramolecular acyl transfer (that does not require heating) and improved assembly of difficult sequences using either Fmoc or Boc SPPS.
This Hmb-backbone substitution approach has led to the recent development of backbone amide linkers (BAL) (Jensen et al., 1998), as shown in Scheme 7.

A tris-alkoxybenzyl unit is employed to link a peptide via the backbone amide nitrogen atom to a solid support. The link is cleaved by simple TFA treatment at the end of the synthesis. This linking strategy, in contrast to most other such strategies, does not make use of the C-terminal carboxylic acid, and can, at least in theory, be used on any amide bond. It is thus especially useful for synthesis of C-terminaly modified peptides or for the on-resin synthesis of head-to-tail cyclic peptides. As for the Hmb group, the first limitation lies in the difficulties of acylating the secondary amine to form the "linked" amide bond. A second problem is that standard Fmoc SPPS leads to almost complete diketopiperazine formation at the dipeptide stage. Special protection strategies need to be employed to avoid this problem.
The most valuable auxiliary strategies for peptide ligation, cyclisation or difficult peptide sequence assembly generate unmodified peptide backbones in the final product. There are three critical features in these auxiliary strategies: introduction, acylation and removal, as illustrated in Scheme 8. The prior art strategies have been successfully applied in a limited number of cases. However, applications of these strategies are severely limited by the difficulties encountered in the acyl transfer step and/or the final auxiliary removal. Often the acyl transfer is very slow, or does not proceed at all.

It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents forms part of the common general knowledge in the art, in Australia or in any other country.
There are at least three requirements needed to make the auxiliary approach more versatile:
1. allow generic introduction of the auxiliary at the N atom,
2. allow more effective acylation of the nitrogen atom, and
3. allow removal of the auxiliary after acylation.
This combination of requirements severely limits the design of novel auxiliaries.
We have surprisingly found that a modification of the molecular fragment that links an oxygen or sulfur atom to the nitrogen atom has a strong accelerating effect on the acylation rate of the nitrogen atom, in contrast to prior art examples. In a particularly preferred embodiment, the modification further allows photolytic cleavage of the covalent bond between the acylated nitrogen atom and the remaining molecular fragment that connects the nitrogen atom with the oxygen or sulfur atom.
This approach is particularly useful in the field of peptide synthetic chemistry for applications such as formation of small cyclic peptides, formation of large peptides through native ligation of smaller peptide fragments, synthesis of "difficult" peptides, and backbone-linking to a solid support. The prior art methods are often not effective, ie. they only work for a small number of examples, and thus are not generic. This invention provides a more versatile approach for the synthesis of small cyclic peptides, ligation of peptide segments, backbone protection and linkage of peptide to resin during solid phase peptide assembly.

This patent is subject to a terminal disclaimer.


A thermoelectric material including a 3-dimensional nanostructure, wherein the 3-dimensional nanostructure includes a 2-dimensional nanostructure connected to a 1-dimensional nanostructure.

1. Field
The present disclosure relates a thermoelectric material, a thermoelectric element and a thermoelectric module including the same, and a method of preparing the thermoelectric material.
2. Description of the Related Art
A thermoelectric phenomenon is a reversible, direct energy conversion from heat to electricity and vice versa, which occurs when electrons and holes move within a material.
One example of the thermoelectric phenomenon includes the Peltier effect, in which two dissimilar materials are connected at a contact point where heat is released or absorbed due to a current applied from the outside. Another example is the Seebeck effect, in which an electromotive force is generated due to a temperature difference between the ends of the dissimilar materials that are connected at the contact point. Another example is the Thomson effect, in which heat is released or absorbed when a current is applied to the material having a predetermined temperature gradient.
When thermoelectric materials are used, low-temperature waste heat may be directly converted to electricity, or heat generated from electricity, thus energy use efficiency may be increased. Also, thermoelectric materials may be applied in various fields to provide devices such as a thermoelectric generator, a thermoelectric cooler, or the like.
The performance of a thermoelectric material is evaluated using a dimensionless figure of merit ZT defined by Equation 1:
                    ZT        =                                            S              2                                    σ                                                                          T                    κ                                    Equation                                                  1
In Equation 1, ZT is a figure of merit, S is a Seebeck coefficient, σ is an electrical conductivity, T is an absolute temperature, and κ is a thermal conductivity.
To increase energy conversion efficiency, a thermoelectric material having a high Seebeck coefficient, a high electrical conductivity, and a low thermal conductivity is desired, but generally, a Seebeck coefficient, an electrical conductivity, and a thermal conductivity have a trade-off relationship.
Because a nanostructure has a small particle size compare to a bulk material, an intragranular density can increase, and thus scattering of phonons at interfaces of the nanostructure can increases. In this regard, thermal conductivity can be decreased, and the trade-off relationship between a Seebeck coefficient and an electric conductivity can collapses due to a quantum confinement effect, and a figure of merit may increase.
A nanostructure may be, for example, a superlattice thin film, nanowires, quantum dots, or the like, but manufacture of such nanostructures is difficult, and a figure of merit in a bulk material is low.
Therefore, a nanostructure that provides a simple manufacturing process and an improved figure of merit in a bulk would be desirable.

Thermoelectric material, thermoelectric element and module including the same, and method of preparing the thermoelectric material

INDUSTRY-ACADEMIC COOPERATION FOUNDATION, YONSEI UNIVERSITY


A core unit for a heat exchanger comprises a pair of headers spaced from one another each defining a fluid space for receiving a fluid therein and each defining a plurality of apertures. A first region comprising a plurality of first tubes extends between the headers and a first fin is disposed between adjacent pairs of the first tubes. A second region comprising a plurality of second tubes extends between the headers and a second fin is disposed between adjacent pairs of the second tubes. A crushable center different than the first and second regions is disposed parallelly between the first and second regions for controllably crushing when the headers are bent.

1. Field of the Invention
The subject invention relates to a core unit for a heat exchanger, and more specifically to a core unit bent relative to an axis perpendicular to a pair of headers such that the headers are bent.
2. Description of the Related Art
Various core units, shown generally at 10 in FIGS. 1 and 2, are known that include bends for fitting into smaller, more compact heating, ventilation, and air conditioning (HVAC) system cabinets. Core units 10 generally comprise a pair of headers 12 spaced from one another for receiving a fluid therein and having a plurality of apertures 14 for connecting a plurality of tubes 16. The tubes 16 are in fluid communication with the apertures 14 for transferring fluid between the headers 12. Fins 18 are disposed between adjacent pairs of tubes 16 for dissipating heat from the fluid in the tubes 16. The fins 18 are generally formed from sheet metal and are formed into a shape of an accordion. The fins 18 may be referred to as corrugated fins or air centers. The fins 18 may also be louvered, i.e., the fins 18 have louvers defined therein to increase heat transfer as is understood by those of ordinary skill in the art.
The core units 10 can be orientated in the HVAC system in various positions. In one orientation of the core unit, the tubes 16 are horizontal and the fins 18 are generally vertically aligned and transverse relative to the tubes 16. Because the convolutions of the fins 18 are up and down and the tubes 16 are horizontal, condensate may collect in the convolutions resulting in inadequate drainage. The condensate accumulation increases the air pressure drop and decreases performance of the core unit. The blockage can also result in ice formation during heat pump heating modes.
Further, it is known to bend the core units 10 so that the core units 10 fit within the cabinet. Generally, the core units 10 are bent about an axis that is parallel to the headers 12 such that the headers 12 are not bent. Bending the core unit in this manner slightly elongates the tubes 16 and only a minimal amount of fins 18 become crushed. The overall performance of the core unit is maintained with such an orientation. Also, the condensate accumulation is still likely to occur when the core unit is positioned having the tubes 16 horizontal.
One solution to overcoming the inadequate drainage is to orientate the core unit such that the tubes 16 are vertical and the fins 18 are generally horizontal and transverse to the tubes 16. The condensate is less likely to collect between the convolutions of the fins 18 when the tubes 16 are vertically aligned.
Prior attempts have been made to bend the core unit about an axis perpendicular to the headers 12 when the tubes 16 are vertical. However, when the core unit is bent, the tubes 16 and fins 18 next adjacent the bend undergo reduced performance. When the header is bent, as shown in FIG. 1, on the inner radius of the bend, the fin between adjacent tubes 16 is crushed thereby reducing and/or preventing fluid flow through the fin. Further, the fins 18 spaced from the axis of the bend may also be crushed as a result of the stress from the force required to bend the headers 12. Air pressure drop increases as a result of the fin collapsing and the thermal performance of the tubes 16 adjacent the crushed fin also is reduced. Experimentally it was determined that bending the headers 12 resulted in approximately fifty percent of fins 18 exhibiting some crushing and therefore lessened thermal properties. The outer radius of the bend, shown in FIG. 2, stretches the fins 18 and stresses the tubes 16 adjacent the bend, which is also undesirable.
The related art core units and methods of forming the same are characterized by one or more inadequacy. Accordingly, it would be advantageous to provide a core unit and a method of forming the same that overcomes these inadequacies.


A sidewall 12 of a tire 10 having a surface with distinctive design patterns is described. Pattern A has a plurality of ridges 20 of similar cross-sectional shapes, each ridge 20 being substantially parallel to an adjacent ridge 20. Pattern B is superimposed over a portion of the design pattern A. Pattern B has a plurality of parallel ridges 30 extending in an angular direction between 45.degree. and 90.degree. relative to the ridges 20 of pattern A. In one embodiment a pattern C is included, pattern C having at least two parallel ridges 40 angularly oriented in the range of 45.degree. to 90.degree. relative to the ridges 20 of pattern A. The ridges 20 of pattern A intersect two ridges 40 of pattern C. The design patterns may form a circumferentially continuous wide decorative band with striped alpha-numeric markings superimposed over a portion of the wide decorative band.

This invention generally pertains to design patterns for opaque articles. More specifically, this invention relates to at least two design patterns used on the surface of a opaque article, the patterns each comprising pluralities of parallel ridges oriented to yield a striking visual appearance.
The invention is particularly applicable to the black sidewalls of rubber tires. However, it will be appreciated by those skilled in the art that the invention has broader applications and may be employed in the manufacture of rubber mats or various other opaque articles.
Manufacturers have for many years placed numerals, letters, characters or other designations upon the sidewalls of tires to enhance the appearance and marketability of their products. Such markings are described in U.S. Pat. Nos. 4,198,744 and 4,823,856.
The subject matter of U.S. Pat. No. 4,198,774, issued Apr. 22, 1980, was invented by Roberts and Lowther. The invention describes the use of lineal projections which are substantially straight, parallel, and of substantially identical cross-section to form indicium. An indicium is described as a letter or numeral or the like.
The latter issued patent of Mr Charles W Roberts, U.S. Pat. No. 4,823,856, issued Apr. 25, 1989, describes the use of serrated outline markings for the sidewall of a tire. The invention relates to a design of a substantially flat ungrooved portion surrounded by a serrated portion which includes a plurality of ribs separated by grooves. The combination of the flat design surrounded by a serrated portion defines an indicium.
The present invention employs the use of at least two distinctive design patterns which improves the visual appearance of an opaque article by increasing the visual contrast of the surfaces of articles. The invention is particularly well-suited for the sidewall of a tire, particularly a black sidewall tire. The combination of design patterns in at least one embodiment of the invention, has the effect of making the sidewall markings boldly stand out when viewed from an angular perspective of 60.degree. or less relative to a plane parallel to the sidewall wall of the tire. The design patterns uniquely change in contrast relative to each other in an inverse relationship as a function of the position of the tire.


A plastic roller furling apparatus includes an elongated member or furling element and a pair of longitudinally extending parallel wires encased therein. The wires of twisted stainless steel are extruded or molded into the member. The member also defines a central opening or passageway which extends therethrough. This passageway is dimensioned or sized to fit loosely around a stay in which the apparatus is installed. The furling element also includes one and preferably two grooved luff foils which are formed in and extended along the length of the plastic member. Split bearing means are also provided at or near the base of the plastic member and a furling drum or jib sail spool is provided for rotating the plastic member about a stay to furl the sail. The plastic member also includes first and second longitudinally extending segments which extend along the length of and divide the plastic member into two pieces. The segments each include fastening means integral thereof for fastening the two segments together along their length. When fastened together the two segments define a central opening for fitting around the headstay of the sailboat. A split body member is also provided and clamps around the elongated plastic member. This split body member may include a first bearing element for engagement with a split bearing which is installed over the stay.

Roller furling systems, such as disclosed in the U.S. Patent of Crall, U.S. Pat. No. 3,789,790 have been in use for many years. Such systems typically include a sleeve or torsion element which surrounds a forward stay on a sailboat. The systems also typically include means such as a jib sail spool which sits on and rotates about a bearing for winding and unwinding i.e., furling or unfurling a sail. Means are also provided for rotating the jib sail spool.
More recent developments such as those disclosed by Hood, U.S. Pat. No. 4,248,281 and Dahmen, U.S. Pat. No. 4,821,664 have facilitated sail changes and led to an increased demand for roller furling devices.
Nevertheless, there are a number of shortcoming associate with the prior art roller furlers and it is believed that there may be a large commercial demand for a roller furler which overcomes those shortcomings. For example, roller furlers are typically installed over an existing headstay and require some disassembly of the standing rigging. For this reason, a number of sailors are intimidated by the installation and then turn to a professional which adds to the cost of the roller furler. Some sailors may also be intimidated by the cost of a typical roller furler and would be attracted to a less expensive device.
It has now been found that a roller furling apparatus in accordance with the present invention overcomes the aforementioned shortcomings and offers a number of advantages over prior art furlers. For example, roller furlers in accordance with the present invention are designed for installation over an existing headstay with a headstay intact and in place. Accordingly, the roller furler can be sold in kit form and be readily installed by relatively unskilled individuals using only readily available tools. In addition, the roller furlers in accordance with the present invention are relatively light in weight and flexible over their length so that they can be coiled for packaging and shipment and at the same time provides torsional rigidly after installation. The roller furling apparatus in accordance with the present invention are also durable, inexpensive to manufacturer and present a pleasing appearance without outward projections which might damage a sail.
A further feature of the present invention resides in a split drum or jib sail spool and free floating line guide which can be installed over an existing headstay with the headstay intact and in place. The split drum and free floating line guide may also be applicable for use with a more conventional furling apparatus which is installed after release of the headstay from the craft.


A crystalline higher α-olefin polymer which is obtained from a C10 or more α-olefin and satisfies either (1) the melting point (Tm) as measured with a differential scanning calorimeter (DSC) is 20 to 100° C. or (2) in an examination of spin-lattice relaxation time (T1) by solid NMR analysis, a single T1 is observed at the temperatures not lower than the melting point; and a process for producing the α-olefin polymer with a specific metallocene catalyst. The crystalline higher α-olefin polymer is excellent in low-temperature characteristics, rigidity, heat resistance, compatibility with lubricating oils, mixability with inorganic fillers, and secondary processability.

Hitherto, there have been made various studies concerning polymerization of higher α-olefins having 10 or more carbon using mainly Ziegler/Natta catalysts.
For instance, the above studies have been reported in "Polymer J.", 10, 619, (1978), "Macromol. Chem.", 190, 2683 (1989), "Makromol. Chem., Rapid Comm.", 13, 447 (1992), Japanese Patent Application Laid-open No. Hei 7-145205, etc.
However, the higher α-olefin polymers described in these literatures tend to have a low molecular weight as well as a high melting point due to a high regularity thereof, and further tend to exhibit a non-uniformity owing to existence of two melting points thereof, etc.
In addition, in "Macromol. Sci. Pure Appl. Chem.", A35, 473 (1998), "J. Polym. Sci.", A, 38, 233 (2000), "Macromol. Mater. Eng.", 286, 480 (2001) and "Macromol. Matr. Eng.", 286, 350 (2001), it is described that higher α-olefin polymers are produced in the presence of homogeneous catalysts called metallocene catalysts.
However, the polymers produced in the presence of such homogeneous catalysts also fail to exhibit a sufficiently high molecular weight, and have a high melting point due to a high regularity thereof, and further show a non-uniformity owing to existence of two melting points, similarly to the above-described polymers obtained using the heterogeneous catalysts.
The polymers having a plurality of melting points tend to be non-uniform in crystal size, etc., which may result in occurrence of stickiness.
Further, when such polymers are blended as a modifier with other resins, the resultant blend tends to be non-uniform, thereby failing to modify properties of the resins as desired.
Also, in the applications such as heat accumulating agents, in order to enhance a heat accumulating efficiency, it is required that resins used therein cause abrupt exothermic or endothermic reaction due to abrupt melting or crystallization thereof at a specific temperature. Therefore, it will be difficult to use the above non-uniform resins in such applications.
Accordingly, an object of the present invention is to provide a crystalline higher α-olefin polymer that is excellent in compatibility with thermoplastic resins, especially polyolefins, compatibility with lubricating oils, fuel oils or waxes, mixability with inorganic fillers and fabricability (secondary processability) and has a narrow melting or crystallization temperature range, and a process producing the same.

Crystalline polymer of higher α-olefin and process for producing the same


In a concatenated code data, correctly decoded code words from a block decoder is utilized to improve the performance of the convolutional decoder. A code word can sometimes be correctly decoded prior to receipt of all the symbols for the code word. Early decoding of the code word allows for the correct recreation of the entire code word, even the symbols which have not yet been received. The entire corrected code word is used by the convolutional decoder to eliminate branches the trellis, thus improving decoding of prior data bits and future data bits in the trellis. The chain back distance of the convolutional decoder can also be made shorter based on the knowledge that some of the received code words have been correctly decoded. Finally, the parity symbols which have not yet been received for the correctly decoded code word can be eliminated from transmission to improve the overall transmission rate.

I. Field of the Invention
The present invention relates to data communications. More particularly, the present invention relates to a novel and improved communication system employing concatenated coding.
II. Description of the Related Art
With the advent of digital communications and the need to transmit large amount of data through an impaired and bandlimited channel, the need for coding of digital data to facilitate correct data reception is of great significance. Data transmissions are typically hindered by impairments in the transmission channel, namely additive noise and spurious signals within the transmission bandwidth. The transmit power is limited by practical considerations and the transmitted signal is attenuated by the path loss and may be distorted by other phenomenon, such as multipath, before it reaches the receiver. The design of a digital communications system entails the determination of the worse case signal quality at which the receiver is expected to operate. This signal quality is measured as an energy-per-bit-to-noise ratio (Eb/No) and is determined by the transmitted power, path loss, and noise and interference. The minimum Eb/No which yields the desired level of performance is considered the system threshold level.
At the threshold level, the probability of error (PE) for any digital transmission scheme such as binary shift keying (BPSK), quaternary phase shift keying (QPSK), or quadrature amplitude modulation (QAM) can be calculated. Typically the PE of the selected transmission scheme is not adequate for the application. Improvement in the PE is achieved by encoding the digital data before transmission and decoding the data at the receiver. The coding scheme is determined by the requirements of the application and the channel characteristic. Coding allows for detection and correction of errors in the transmitted data at the expense of a lower effective data rate.
Two classes of coding, block coding and convolutional coding, are utilized to improve PE. Convolutional code provides good error correcting capability but typically outputs correlated bursts of error. Also, the Viterbi decoder supports the use of soft decisions to improve performance with minimal increase in hardware complexity. Block codes have built in burst error handling capability when combined with the proper level of interleaving. In fact, a single error correcting Reed-Solomon block code could handle any burst of errors within a single symbol. When convolutional coding alone would not produce the required coding gain, a concatenated code comprising a convolutional code and a block code can be used.
A Reed-Solomon code is a powerful non-binary, cyclic, and linear block code that achieves the largest possible code minimum distance (d.sub.min) for any linear code with the same input (k) and output (n) block length. In this specification, lower case symbols are used to denote variables for the block code and upper case symbols are used to denote variables for the convolutional code. Reed-Solomon coding is well known in the art and a good treatment of the topic is found in a number of references, including "Error Control Coding: Fundamentals and Applications" by S. Lin and D. Costello", Prentice Hall, 1985, pgs. 171-176. In a non-binary code, m bits of data are combined to form a symbol. For an (n,k) Reed-Solomon code, blocks of k data symbols are encoded into blocks of n code symbols called Reed-Solomon code words. The (n,k) Reed-Solomon code is capable of correcting up to (n-k)/2 symbol errors within a block of n symbols. Since n code symbols are transmitted for k data symbols, the code rate, or reduction in the data rate, is k/n.
In a systematic block code, the k data symbols form the first k code symbols of the code word. The n-k parity symbols are formed by a linear combination of the k data symbols according to the generator polynomial g(x). Because of the linear, systematic, and cyclic properties of the Reed-Solomon code, the encoding process is easily achieved with simple shift registers and combinatory logic. The first step in the decoding process involves calculating a set of syndromes from the received n code symbols. The syndromes indicate the location and values of the symbol errors. In particular, the coefficients of the error location polynomial, .sigma.(x), are calculated using the syndromes and from this, the error locators Xi and the error values Yi are computed. With the error locators and error values, the symbols in error are located and corrected.
A rate 1/N convolutional encoder encodes each input bit into N code bits called a code branch according to a set of N generator polynomials. Each generator polynomial G(x) computes one code bit. The N code bits are combined into an N-bit code branch. The constraint length K of the encoder is the number of data bits used in the encoding process and determines the error correcting capability of the code. Long constraint length K yields better performance at the expense of hardware and computational complexity. A state is designated by the K-1 prior input bits and there are 2.sup.K-1 possible states. For each of the 2.sup.K-1 states, a `0` or `1` input bit results in one of two possible code branches. Since each input bit is encoded into N code bits, the code rate for the convolutional encoder is 1/N. Other code rates could be obtained from a 1/N code by puncturing the code bits. Punctured codes are thoroughly treated by J. Cain, G. Clark, and J. Geist in "Punctured Convolutional Codes of Rate (n-1)/n and Simplified Maximum Likelihood Decoding," IEEE Transaction on Information Theory, IT-25, pgs. 97-100, January 1979.
A Viterbi algorithm is used to decode the transmitted code branches at the receiver. A discussion on the theory and operation of the Viterbi decoder is contained in the paper "Convolutional Codes and Their Performance in Communication Systems" by A. Viterbi, IEEE Transaction on Communication Technology, Vol. COM19, no. 5, October 1971, pgs. 821-835. Under certain assumptions about the channel noise, the Viterbi algorithm performs the maximum likelihood decoding of the transmitted data path. For each received code branch, the branch metric of all branches entering each state is computed and added to the corresponding prior path metrics. The best path entering each state is selected and stored as the new path metrics. The selected path is stored in a path memory. In "Development of Variable Rate Viterbi Decoder and its Performance Characteristics," Sixth International Conference on Digital Satellite Communications, Phoenix, Ariz., September 1983, Y. Yasuda et al. show that the survivor paths with the lowest path metric all converge to the same path after a certain chain back depth. Thus, a Viterbi decoded bit is obtained by tracing a path back by at least the chain back distance.
Interleavers and de-interleavers are utilized to combat channel characteristic and to maximize the code effectiveness. In a system in which the channel is not memoryless, bit errors at the receiver occur in bursts. The performance of the Viterbi decoder is better when the Viterbi decoder input contains non-burst type errors. Thus, a de-interleaver before the Viterbi decoder spreads the channel burst errors and `whitens` the errors. Also, a Viterbi decoder has tendency to output bursts of correlated errors in the decoding process. Therefore, a de-interleaver after the Viterbi decoder spreads the burst errors from the Viterbi decoder over different Reed-Solomon code words. The depth of the de-interleaver determines the length of the burst errors which will be successfully handled by the system.
Typically, once a communication system has been designed, data are encoded and transmitted according to the concatenated code. All data bits are encoded and all code bits are transmitted.

Method and apparatus for transmitting and receiving concatenated code data


There are provided an acoustic wave image generating apparatus for generating a B-mode image having a fixed brightness and a control method thereof. First brightness information (81) indicating the brightness of a first B-mode image in the depth direction of the subject is generated. Positional deviation correction is performed on an acoustic wave echo signal having a positional deviation between the focusing position of acoustic waves and the observation target position, and second brightness information (82) indicating the brightness in the depth direction of the subject is generated from a superposition signal obtained by superimposing an acoustic wave echo signal for which the positional deviation has been corrected and an acoustic wave echo signal without positional deviation. The brightness of the first B-mode image is corrected based on the first brightness information and the second brightness information.

1. Field of the Invention
The present invention relates to an acoustic wave image generating apparatus and a control method thereof.
2. Description of the Related Art
Generally, an ultrasound image is bright in the vicinity of a position where ultrasound waves are focused, and becomes dark as a distance from the position increases. For this reason, transmitted sound waves of the ultrasound beam are calculated, and different gains are adjusted for each depth based on the calculation result (JP2012-217583A). In addition, there is a method of generating a piece of element data from a plurality of pieces of element data in consideration of propagation time using element data before phasing addition and generating an image by performing phasing addition (JP2014-030715A). According to this, it is possible to obtain an image with little gain deviation for each depth.

Acoustic wave image generating apparatus and control method thereof


Disclosed is an apparatus for determining a flow of a medium through a pipe, as well as a method for operating the apparatus. The apparatus comprises a heating element at least partially in thermal contact with the medium and which is heatable by means of a heating signal, and a first temperature sensor for registering a temperature of at least one component of the apparatus or the temperature of the medium. The heating element and the first temperature sensor are arranged outside of the pipe. The apparatus includes at least one coupling element, which is at least partially in thermal contact with the heating element, the first temperature sensor and/or a portion of the pipe or tube and serves to assure a thermal coupling between the heating element and the first temperature sensor and between the heating element and the medium.

Thermal, or calorimetric, flowmeters find multiple application in process- and/or automation technology. Corresponding field devices are produced in a wide variety of embodiments by the applicant and are sold, for example, under the marks, t-switch, t-trend, t-mass, or Flowphant. The underpinning measuring principles are known from the state of the art. The terminology, flow, includes in the context of the present invention both volume flow as well as also mass flow of the medium. Likewise, a flow velocity of the medium can be ascertained. Fundamentally, flow can be determined in two different ways.
According to a first measuring principle, a sensor element is exposed to a medium flowing through a pipeline and heated in such a manner that its temperature remains essentially constant. In the case of known and at least at times constant properties of the medium, properties such as the temperature of the medium, its density or even its composition, the mass flow of the medium flowing through the pipeline can be ascertained from the heating power needed for holding the temperature at the constant value. The terminology, temperature of the medium, refers, in such case, to that temperature, which the medium has without an additional heat input of a heating element.
In the case of an alternative measuring principle, the heating element is, in contrast, operated with constant heating power and the temperature of the medium downstream of the heating element measured. In such case, the measured temperature of the medium provides information concerning mass flow.
In the case of both described measuring principles, especially in the case of variable temperature of the medium, moreover, a second sensor element, for example, a temperature sensor, can be used for temperature measurement of the medium.
The heating elements of thermal flowmeters are frequently in the form of resistance heaters. For example, so-called resistance elements, e.g. RTD resistance elements (Resistance Temperature Detector), especially platinum elements, are applied, such as commercially obtainable under the designations PT10, PT100, and PT1000. The resistance elements are heated via the conversion of electrical power supplied to them, e.g. as a result of an increased electrical current supply.
The determining and/or monitoring of volume flow mass flow, and/or flow velocity, is based fundamentally on the fact that the thermal contact resistance between the sensor element and the flowing medium changes as a function of flow velocity. If there is, for example, no flow present in the pipeline, the registering of the heat from the heating element occurs via heat conduction, heat radiation and, in given cases, also via free convection within the medium. For maintaining a certain temperature difference according to the first of the two described measuring principles, then, for example, an amount of heat constant with time is required. In the case of the presence of a flow, in contrast, there results an additional cooling of the sensor element by the flowing, especially colder, medium. An additional heat transport occurs due to forced convection. Correspondingly, as a result of a flow, an increased heating power must be supplied, in order to be able to maintain a fixed temperature difference relative to the temperature of the medium. Similar considerations hold for the second of the two described measuring principles.
The relationship between the heating power, or measured temperature, and the flow and/or flow velocity of the medium through the pipeline can also be expressed by means of the so-called heat transfer coefficient. In addition, different thermophysical properties of the medium as well as the pressure reigning in the pipeline have an influence on the measured flow. In order, for example, also to take the dependence of flow on these variables into consideration, different thermophysical properties in the form of characteristic lines or components of functional equations are stored within an electronics unit of the flowmeter.
For a high accuracy of measurement, basically, the thermal contact between the heating element and the flowing medium is decisive. Thus, for example, a change of thermal resistance of the heating element, which leads to a change of the heat transfer from the heating element to the medium in the case of otherwise constant flow conditions, can bring about considerable measured value error. A change of thermal resistance caused in such a manner is also referred to as sensor drift.
Regarding thermal resistance in a flowmeter, a distinction is made between inner thermal resistance and outer thermal resistance. The inner thermal resistance depends, among other things, on individual components within the sensor element, e.g. within a sleeve thereof. Thus, a sensor drift can occur as a result of defects occurring in soldered connections due to tensile loads from material expansion or the like. The outer thermal resistance is influenced, in contrast, by accretion formation, material removal or material transformation (e.g. corrosion) on the surfaces of the sensor element contacting the medium. A change of the outer thermal resistance is, thus, relevant especially over long periods of operation and/or in the case of contact with aggressive media. In the case of gaseous- or vaporous media, the measurement of mass flow or flow velocity can, moreover, be degraded also by condensation on at least one of the temperature sensors.
For registering volume flow, mass flow and/or flow velocity, the heating element is brought at least at times and/or partially into thermal contact with the medium. In this regard, the heating element is usually at least partially introduced into the pipeline or integrated into a sensor head, which is installable into an existing pipeline. By integrating the sensor element into a pipe or tube, a fast response time and high accuracy of measurement of the measuring device can be assured, since a change of the thermal contact resistance between the heating element and the flowing medium is then essentially directly detectable.
However, for certain applications, it can also be disadvantageous that the sensor unit protrudes inwardly into the process. Relevant here, on the one hand, is the installation or replacement of the measuring device, which requires then directly interacting with the process. Moreover, a sensor unit protruding into the process also influences the flow of the medium in the pipe.
Non-process contacting measuring devices for determining flow are known, for example, in the form of clamp-on, ultrasonic, flowmeters. In the case of such devices, the sensor unit is securable externally on the pipe or tube and does not protrude into the process. Such measuring devices are manufactured by the applicant and sold, for example, under the designation, Proline Prosonic.
When applying the thermal, or calorimetric, measuring principle, a construction of such type without a direct contact with the process is significantly more difficult to implement. For example, the particular pipe or tube conveying the medium as well as the external environment of the pipe or tube, especially the ambient temperature, have a large influence on the thermal behavior of the measuring device, and on the heat flow between the heating element, medium and, in given cases, the temperature sensor. Thus, an external positioning of the sensor unit of a thermal, or calorimetric flowmeter leads to a lessened response time to flow changes and, in given cases, also to a lower accuracy of measurement compared with a process contacting device.

Thermal flowmeter including a coupling element with an anisotropic thermal conductivity


In a method for the making of a lateral bipolar transistor, the formation of a field oxide layer on the surface of the substrate, between the collector and the emitter of the protection transistor, is avoided. The lateral bipolar transistors made by the disclosed method are advantageously used to protect MOS type integrated circuits against electrical discharges.

The invention relates to a method for making a bipolar transistor providing protection against electrostatic discharges in an integrated circuit.
Integrated circuits are generally highly sensitive to electrostatic discharges. Indeed, these discharges result in excess voltages that are short-lived but have high values that may go up to several kilovolts in peak voltage, and induce instantaneous dissipated power values of several tens of Watts. These electrostatic discharges are likely to cause deterioration in the working of the integrated circuits and may even destroy these circuits, for example by excessive heating. It is therefore vitally necessary to take steps against this type of phenomenon by placing protective devices at the input of the integrated circuits.
A first type of protection consists of the connection of limiter diodes between input points of integrated circuits and supply terminals of these integrated circuits. This approach notably has the drawback of being restrictive for the threshold voltages of these diodes limits the range of the values permitted at these input points in normal operation.
Increasingly, therefore, a second protective device using bipolar transistors is being resorted to.
Let it be assumed, for example, that the protective device relates to an integrated circuit that is powered between a positive voltage and a ground and has one input, and that it is sought to protect this integrated circuit against electrostatic discharges of positive voltages.
The integrated circuit is protected by connecting an NPN type bipolar transistor between its input and the ground. The collector is connected to the input of the integrated circuit. The base and the emitter are connected to the ground. The transistor is therefore off in the absence of any electrostatic discharge. For, it is assumed that the voltage values permitted by the manufacturer at input of the circuit are lower than the avalanche voltage value of the protective bipolar transistor. In the event of electrostatic discharge, the protective transistor limits the excess voltage characterizing this discharge. Indeed, the excess voltage prompts an avalanche phenomenon in the protective transistor.
From the technological point of view, the integrated circuits are made notably by metal-oxide-semiconductor (MOS) technology.
With regard to the making of bipolar transistors for the protection of MOS type integrated circuits, it is advantageous to make bipolar transistors without superimposed layers. Indeed, the making of this type of structure requires more steps to be performed than the making of MOS type circuits. It is therefore desirable to integrate the manufacturing of the protective bipolar transistors into the process of manufacturing the MOS type circuits that they protect. This makes it possible to avoid having to add diffusion steps to those already required for the manufacture of a MOS type circuit. Consequently, lateral type bipolar transistors are preferably made for this use.
The method of manufacturing a lateral bipolar transistor of an NPN type in the example chosen typically includes the following basic operations:
the preparation of a P type substrate, PA1 the creation, on the surface of the substrate, of a field oxide layer by thermal oxidation, this layer demarcating two source/drain type implantation zones, PA1 the implantation of N type dopants in the implantation zones and the diffusion of these dopants in the underlying semiconductor substrate, PA1 the vapor phase deposition of an insulator layer on the circuit, PA1 the opening of contacts in the implantation zones, PA1 the metallization of the contacts. PA1 a semiconductor substrate implanted with a first type of dopant in a certain concentration, PA1 a field oxide layer covering a part of the semiconductor substrate, the uncovered part forming an active zone, PA1 two distinct implantation zones implanted with a second type of dopant in the active zone, PA1 a separation zone, in the active zone, between these implantation zones, PA1 a layer of an insulator deposited on the surface of the transistor after the implantation of the implantation zones, this layer of insulator being in contact with a part of the implantation zones and the separation zone, and wherein the deposited insulator is in contact with the semiconductor substrate at the position of the separation zone.
The implantation zones are zones known as active zones. An active zone is a surface zone of the substrate covered with thin oxide. An active zone such as this is therefore capable of being doped by implantation. Hereinafter, the term "implantation zone" will characterize the active zones that are actually implanted during the manufacturing process. In the example, the implantation or active zones, with their underlying N type diffusion, form the emitter and the collector (hereinafter called electrodes) of the bipolar protective transistor.
The base of the bipolar transistor is constituted by the substrate, the latter being connected to the ground. In practice, the useful base of the transistor is that part of the substrate that is located between the N type diffusions of the emitter and of the collector. The term "useful base" designates the base zone that comes into play in the transistor effect.
The implantation zones are demarcated by the field oxide on the surface of the substrate. Indeed, the field oxide counters the passage of the dopant particles. It therefore insulates the substrate during the doping operations. The implantation zones are characterized by the fact that they are not covered with field oxide.
The making of the implantation and of the diffusion of N type dopants in the implantation zone is integrated into the process for making a MOS type circuit. There is no stacking of three layers with successive N, P and N type doping.
It is possible, before the creation of the field oxide, to carry out a P type implantation and diffusion in the zones that will be covered by the field oxide. Thus, by diffusion, insulator walls known as channel stops are created between the emitter and the collector on the one hand, and between these electrodes and the rest of the circuit on the other hand. Since the substrate is initially a P type substrate, the concentrations of impurities in the insulation wells are naturally greater than that of the substrate.
The insulation wells enable the prevention of a piercing of the transistor, namely a passage of leakage current between the electrodes. Furthermore, these insulator diffusions diminish the formation of parasitic MOS type transistors whose gates would be formed by interconnections passing over the implantation zones.
This method has a drawback. Indeed, it has been observed that, after an electrostatic discharge, leakage currents could appear, in normal operation, between the collector and the base. The term "normal operation" is understood to mean operation that induces no conduction in the protective bipolar transistor.
It has been discovered that these leakage currents are due to the injection of hot carriers into the field oxide between the electrodes, similarly to the phenomenon of ageing of the MOS type transistors. This injection occurs in a region of the field oxide known as the "bird's beak". A bird's beak is a particular feature, shaped like a spike, located at the boundary of a field oxide and a surface of a thermally non-oxidized substrate. It is caused by the lateral oxidation of this substrate.
A hot carrier is the name given to a carrier (in this example an electron) accelerated by the field resulting from an electrostatic discharge and capable of acquiring sufficient energy to overcome the potential barrier of the field oxide. This injection occurs at the bird's beak placed at the boundary of the field oxide between the electrodes, and of the collector of the transistor. This injection remains limited as the carriers are hampered by the field oxide. An electrical field is created at the surface of the field oxide, on the collector side, and induces a leakage current between the collector and the substrate of the transistor.
In view of the above, the aim of the present invention is to propose a method for the making of a protective lateral bipolar transistor that can be used to eliminate the leakage currents that appear in normal operation, after a discharge.
The approach proposed by the invention is that of eliminating the field oxide zone which the injection of hot carriers occurs into, inducing leaks. This field oxide zone is the one between the two implantation zones corresponding to the electrodes of the bipolar transistor. It therefore covers the useful base of the bipolar transistor.
According to the invention, this aim is achieved by implementing a method for the manufacture of a protective bipolar transistor for protection against electrostatic discharges in an integrated circuit, comprising, in the following order, masking operations enabling the demarcation, for this bipolar transistor, on the surface of a semiconductor substrate, of two implantation zones and a separation zone between said implantation zones, and an operation for the implantation of the implantation zones with impurities enabling the selective doping of these implantation zones, wherein the masking operations comprise a first step with a total or overall contour masking operation to make a field oxide around an active zone encompassing the implantation zones and a second step with a masking enabling the separation, within this active zone, of the differentiated implantation zones, and wherein, subsequently to the operation for the implantation of the implantation zones, an operation is carried out to cover a part of the implantation zones and of the separation zone with a deposited insulator, this insulator being deposited against the surface of the semiconductor substrate at the position of the separation zone.
This thus prevents the injection of hot carriers into the bird's beak of the field oxide, at the separation zone of the implantation zones, on the collector side. The bird's beak has disappeared at this position.
The elimination of the field oxide between the implantation zones calls for steps to be taken with respect to the masks used during the operations for the thermal oxidation and doping of the implantation zones. Indeed, the demarcation of the implantation zones was previously obtained by the field oxide. The field oxide covered the separation zone between the implantation zones.
The method according to the invention makes it possible to dope the implantation regions selectively, by masking the separation zone temporarily during the doping of the implantation zones.
Thus, during the masking operations, there is made a field oxide that does not cover the implantation zones and the separation zone between the implantation zones. The separation zone between the implantation zones is masked temporarily during the operation for the implantation of the implantation zones, only the implantation zones being doped during this operation.
Hence there is no more than just one active zone (namely a zone covered with thin oxide) instead of two as was the case previously. This active zone includes the two implantation zones and the separation zone between said zones.
Usually, the implantation masks are generated automatically by a computer program, on the basis of the mask demarcating the active zones and information elements defining the type of doping (N or P) of these zones. It is therefore not usual to take action at these levels. Indeed, in MOS technology, the diffusions of a same type are either separated by a gate to form a MOS transistor or separated by field oxide.
The invention can be used to make a bipolar transistor providing protection against electrostatic discharges in an integrated circuit, comprising:
said device comprising
In standard MOS technology, the insulator deposited is in contact with MOS type transistor gates, field oxide zones and implantation zones.

Method for making a bipolar transistor for the protection of an integrated circuit against electrostatic discharges


The present application provides a compressor manifold assembly. The compressor manifold assembly may include a suction manifold with a number of suction manifold modules, a discharge manifold with a number of discharge manifold modules, and a number of compressors positioned on the suction manifold and the discharge manifold.

Retail stores such as supermarkets and the like generally have a number of refrigerated display cases with food and/or beverages therein. A number of the refrigerated display cases may be operated within a central refrigeration system. Such a refrigeration system may include an evaporator and a fan mounted about each refrigerated display case for cooling the items therein, an external condenser, and a number of compressors. Generally described, a refrigerant fluid is heated and expanded in the evaporators while removing heat from the refrigerated display cases. The compressors compress the heated refrigerant gas and force the refrigerant to the condenser. The condenser transfers heat from the refrigerant and condenses the refrigerant such that the cycle may be repeated. The refrigeration system may use extended discharge and suction lines between the several components.
The compressors are generally arranged in a parallel configuration. Each of the compressors thus may be in communication with a discharge header and a suction header for the flow of refrigerant. Such an arrangement, however, may result in a complex configuration of compressors, piping, and the like. Moreover, all of the components generally may not be uniform such that adding or removing compressors or other components within the overall refrigeration system may be time consuming and difficult.
There is thus a desire for an improved refrigeration system in general and, more particularly, an compressor manifold assembly and configuration. Such an compressor manifold assembly and configuration may provide substantially uniform components for ease of support, installation, and repair.


A geometric-shaped core for a golf ball has a plurality of outwardly extending projections formed on a spherical central portion thereof. A layer of a relatively less resilient material is applied in the interstitial space between the projections on the surface of the core, and a cover is applied over the core and interstitial layer. The geometric-shaped core is manufactured by first providing flexible, resilient, honeycombed inserts to be used in a conventional compression mold. The inserts are placed into the upper and lower mold cavities, the core material is added, and the geometric-shaped golf ball core is compression molded.

Golf balls are generally classified as one of two construction types: wound construction and solid construction. Wound balls typically contain a solid or liquid center, elastomeric thread windings about the center, and a cover. Solid balls typically contain a solid polymeric core and a separately formed cover. Additional polymeric layers optionally may be interposed as intermediate layers between the center or core and the cover in each of the wound and solid construction types to obtain desired performance characteristics. It is generally understood in the art that solid balls may provide better initial velocity, distance and durability than wound balls, while wound balls may provide better feel and control than solid balls.
Due to the perceived inadequacy in terms of control and feel of some solid balls relative to wound balls, the art has proposed several modifications of conventional solid ball materials and construction in order to provide playability characteristics more closely resembling or even exceeding those of wound balls, while still retaining the preferred characteristics found in solid balls. Some of these proposed modifications include providing softer materials in the core, and adding a relatively soft intermediate or mantle layer over a conventional hard polybutadiene core. See, for example, U.S. Pat. No. 5,556,098. While these proposed modifications are directed to achieving better feel and control in a solid ball, they generally do so through a compromise of the distance and durability otherwise found in the unmodified solid ball. There therefore continues to exist a need for a golf ball construction type that optimizes the various performance characteristics such as durability, distance, initial velocity, control, and feel.
In terms of core materials for use in conventional solid ball construction, solid cores are typically compression molded from a slug of uncured or lightly cured elastomer composition comprising a high cis content polybutadiene and a metal salt of an .alpha., .beta., ethylenically unsaturated carboxylic acid such as zinc mono or diacrylate or methacrylate. To achieve higher coefficients of restitution in the core or to increase core weight, the manufacturer may include a small amount of a metal oxide such as zinc or calcium oxide. Other materials used in the core composition include compatible rubbers or ionomers, and low molecular weight fatty acids such as stearic acid. Free radical initiator catalysts such as peroxides are admixed with the core composition so that on the application of heat and pressure, a complex curing or cross-linking reaction occurs.
In terms of core geometry in solid ball construction, the prior art generally teaches the use of a smooth spherical core for use in conventional solid golf balls. The spherical core construction has heretofore been believed to provide adequate performance while at the same time being the most efficient shape for use in conventional golf ball manufacturing processes. There have been variations proposed, however, such as in U.S. Pat. No. 4,229,401 and related U.S. Pat. No. 4,173,345, in which the inventors disclose a core having a series of narrow shallow surface channels each lying on great circles passing through opposite pole areas of the core. The purpose of the surface channels is to prevent the formation of air pockets between the core and cover when the cover is molded onto the core. Similarly, in U.S. Pat. No. 1,558,706, the inventors disclose a core having a surface roughened by corrugations to prevent relative movement of the cover on the core during use of the ball. In U.S. Pat. No. 698,516, there is shown a gutta-percha core (A) having indentations or perforations formed thereon, and a celluloid casing (B) formed over the core. The purpose of the indentations or perforations is to "key" the celluloid casing upon the gutta-percha shell. Finally, in U.S. Pat. No. 743,105, the inventors disclose a golf ball in which the inner surface of the cover and outer surface of the core are each provided with matching projections to give the ball an improved resilient action when struck by a club. Due to the nature of these previously proposed golf ball core modifications, none is directed to improving the control and feel of a solid golf ball; they are instead directed to, respectively, improved manufacturing ability, durability, and resilience.
There therefore continues to exist a need for a golf ball that provides the distance and durability of a solid ball construction, while at the same time providing the control and feel similar to that provided by a wound ball.


A denormalized dataset, an associated primary key field, one or more associated secondary key fields and information identifying one or more normalized datasets associated with each secondary key field, is received. A denormalized table comprising fields and data types corresponding to said denormalized dataset, said denormalized table having a primary key field corresponding to said primary key field associated with said denormalized dataset, is created. The said information identifying the one or more normalized datasets associated with each secondary key field, creating one or more normalized tables, each of said one or more normalized tables corresponding to a respective one of said one or more normalized datasets, each of said one or more normalized tables comprising a foreign key corresponding to said associated primary key and a primary key corresponding to the secondary key field associated with said normalized dataset, is utilized. Additionally, each of said foreign keys is utilized.

The present invention relates generally to the field of denormalized datasets, and more particularly to executing database queries on abstracted denormalized datasets in a relational database management system (RDBMS) environment.
Normalized data datasets can be denormalized by adding redundant data or grouping data from the normalized datasets. Redundant or duplicate items may impact the results of search queries which can be executed to the denormalized datasets, as well as impact the final figures for the denormalized datasets. Final figures gathered for denormalized datasets can include counts, average, standard deviation and other statistical information, which can be distorted from duplicate items in the denormalized datasets.

Abstracting denormalized data datasets in relational database management systems

International Business Machines Corporation