A method for preparing a wide range of substituted poly(aniline)s from a single precursor is described. The method uses a variety of reactions, including a boron activation/electrophilic displacement reaction resulting in ipso-substitution. The ability to tune the properties of poly(aniline) through the generation of new structures is useful in numerous fields ranging from polymer-based electronics to sensors.

This invention relates to methods of synthesizing substituted poly(aniline)s. More particularly, the invention relates to the use of poly(aniline boronic acid) as a precursor in these methods.
Substituted poly(aniline)s are of great interest for a variety of applications ranging from polymer-based electronics to sensors, as well as numerous electrocatalytic applications. As a result, there has been considerable interest in developing new synthetic approaches for their production.
Typically, these substituted polymers are generated by the oxidative polymerization of the corresponding monomer. See, for example, Pringsheim, et al., Anal. Chim. Acta 357:247-252 (1997). However, in many cases the desired moiety is either too difficult to oxidize or is sensitive to oxidative or acidic conditions. One alternative method involves the use of a monomer containing a reactive substituent group to synthesize a precursor polymer that subsequently can be modified to form the desired structure Tsuchida, et al., Macromolecules 26, 7389-7390 (1993).
Boronic acid groups are reactive and provide a versatile chemical precursor for various transformations with isolated yields typically greater than 90%. Examples of such transformation reactions are illustrated in Schemes 1-9.
Aromatic boronic acid groups can be used for transformations via ipso-hydroxylation under mild conditions (Simon, et al., J. Org. Chem. 66:633-634 (2001)). A boron activation/electrophilic displacement mechanism giving this ipso-substitution has been proposed, as shown in the following Scheme 1:
Simon also describes the regioselective oxidation of arylboronic acids to phenols and their one-pot conversions to symmetrical diaryl ethers under mild conditions (room temperature).
Aromatic boronic acid groups can be used for transformations via ipso-halogenation under mild conditions ((i) Nesmeyanov, et al., Chem. Ber. 93:2717 (1960); and (ii) Kuivila, et al., J. Org. Chem. 76:2679-2682 (1954) and Thiebes, et al., Synlett 141-142 (1998)). A boron activation/electrophilic displacement mechanism giving this ipso-substitution has been proposed, as shown in the following Scheme 2:
Aromatic boronic acid groups can be used for copper-mediated cross-coupling with alkyl thiols (Herradura, et al., Org. Lett. 2(14):2019-2022 (2000)), as shown in the following Scheme 3:
Aromatic boronic acid groups can be used for a trans-metallation reaction, as shown in the following Scheme 4:
Aromatic boronic acid groups can be used for copper carboxylate-mediated, catalyzed thioalkyne cross-coupling reactions to produce substituted alkynes (Savarin, et al., Org. Lett. 3(1):91-93 (2001)), as shown in the following Scheme 5:
Aromatic boronic acid groups can be used for cross-coupling reactions with thiol avarin, et al., Org. Lett. 2(20):3229-3231 (2000)), as shown in the following Scheme 6:
Aromatic boronic acid groups can also be used in a reaction that is widely known as the Suzuki cross-coupling reaction. This coupling reaction is an extremely powerful route to produce Cxe2x80x94C bonds under mild conditions (Suzuki, Pure Appl. Chem. 63:419 (1991) and Badone, et al. J. Org. Chem. 62:7170-7173 (1997)), as shown in the following Scheme 7:
Aromatic boronic acid groups can be used for the synthesis of organoborane compounds (Vogels, et al., Can. J Chem. 77(7):1196-1207 (1999)), as shown in the following 8:
Aromatic boronic acid groups can be used for transformations via ipso-nitration under mild conditions (Salzbrunn, et al., Synlett 1485-1487 (2000)). A boron activation/electrophilic displacement mechanism giving this ipso-substitution has been proposed, as shown in Scheme 9.
In spite of the advances in the art, there continues to be a need to develop synthetic strategies for the synthesis of this useful class of compounds. For example, conventional methods of producing diaryl ethers such as Ulman reactions require activated substrates (Patai, The Chemistry of the Hydroxyl Group, Part 1, Wiley, New York, 1971) and high temperature conditions (140-160xc2x0 C., Cohen, et al., Tetrahedron Lett. 3555-3558 (1974), and Cohen, et al., J. Am. Chem. Soc. 88, 4521-4522 (1966)). Accordingly, it is desirable to develop synthetic routes that avoid the need for such activated substrates and high temperatures.
Other problems associated with current methodologies relate to side reactions that occur, resulting in a variety of products that can result from a single reaction. An important example of a substituted poly(aniline) whose structure is complicated by side reactions occurring during oxidative polymerization of its monomer 1, is poly-(hydroxyaniline) 4, as shown in the scheme below:
The structure of the polymer produced by the electrochemical oxidation of 1 is complicated due to the similar oxidative reactivity of both xe2x80x94NH2 and xe2x80x94OH groups as well as the loss of xe2x80x94NH2 to form 2. Several reports exist in the literature regarding whether a ladder 3 or linear 4 polymer is formed (Kunimura, et al., Macromolecules 21:894-900 (1988); Ohsaka, et al., Electrochim. Acta 33:639-645 (1988); Barbero, et al., J. Electroanal. Chem. 263:333-352 (1989); Barbero, et al., J. Electroanal. Chem. 291:81-101 (1990); Goncalves, et al., J. Electroanal. Chem. 487:90-99 (2000); and Zhang, et al. J. Electroanal. Chem. 373:115-121 (1994)). Evidence has been presented that suggests both forms are possible. Accordingly, it is desirable to develop synthetic routes that provide for the exclusive generation of the desired product, for example compound 4.
Additional problems associated with current methodologies relate to the synthesis of compounds such as halogen-substituted poly(aniline)s, which are difficult to synthesize using standard approaches (Dao, et al., Synth. Met. 29:E377-382 (1989) and Pringsheim, et al., Anal. Chim. Acta 357:247-252 (1997)). For example, during standard oxidative polymerization conditions, halogen-substituted anilines have been known to undergo elimination, resulting in the loss of a significant amount of halogen (4-48% for Cl and Br) in the resulting polymer (Snauwaert, at el., Synth. Met. 16:245-255 (1986)).
The present invention addresses these needs by using poly(aniline boronic acid) as the precursor in the synthesis of a wide range of substituted poly(aniline)s.
One aspect of the invention relates to a method of synthesizing a substituted poly(aniline), comprising reacting poly(aniline boronic acid) with a reagent to produce a substituted poly(aniline) of formula I:
where n is an integer within the range of about 1-10,000,000; Ra, Rb and Rc are independently selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; and Z is a substituent produced by the reaction of the reagent and the boronic acid substituent.
Another aspect of the invention pertains to a method of synthesizing a substituted poly(aniline), comprising: reacting poly(aniline 3-boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; to produce a substituted poly(aniline) of formula I, where n is an integer within the range of about 1-10,000,000; Ra, Rb and Rc are independently selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; and Z is a substituent produced by the reaction of the reagent and the boronic acid substituent.
Yet another aspect of the invention relates to a method of synthesizing a substituted poly(aniline) comprising reacting poly(aniline boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; stopping the reaction before all of the boronic acid substituents in the poly(aniline boronic acid) undergo oxidation, substitution or cross-coupling; to produce a substituted poly(aniline) of formula Ixe2x80x2:
where n is an integer within the range of about 1-10,000,000; Ra, Rb and Rc are independently selected from the group consisting of xe2x80x94H, alkyl, xe2x80x94B(OH)2, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; and wherein each Zxe2x80x2 is independently selected from the group consisting of xe2x80x94B(OH)2 and substituents produced by the reaction of the reagent and the boronic acid substituent, with the proviso that at least one Zxe2x80x2 substituent is a substituent produced by the reaction of the reagent and the boronic acid substituent.
Still another aspect of the invention pertains to a method of synthesizing a substituted poly(aniline) comprising: reacting poly(aniline boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; to produce a substituted poly(aniline) of formula I:
where n is an integer within the range of about 1-10,000,000; Ra, Rb and Rc are independently selected from the group consisting of xe2x80x94H, alkyl, xe2x80x94B(OH)2, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; and wherein each Z is the same or different and is a substituent produced by the reaction of the reagent and the boronic acid substituent.
The present invention provides a method for preparing a wide variety of substituted poly(aniline)s from a single precursor, poly(aniline boronic acid). Numerous reactions, including a boron activation/electrophilic displacement reaction that results in an ipso-substitution, provides for the generation of many possible structures such as poly(hydroxyaniline) and halogenated poly(aniline)s.
Before describing detailed embodiments of the invention, it will be useful to set forth definitions that are used in describing the invention. The definitions set forth apply only to the terms as they are used in this patent and may not be applicable to the same terms as used elsewhere, for example in scientific literature or other patents or applications including other applications by these inventors or assigned to common owners. The following description of the preferred embodiments and examples are provided by way of explanation and illustration. As such, they are not to be viewed as limiting the scope of the invention as defined by the claims. Additionally, when examples are given, they are intended to be exemplary only and not to be restrictive. For example, when an example is said to xe2x80x9cincludexe2x80x9d a specific feature, that is intended to imply that it may have that feature but not that such examples are limited to those that include that feature.
It must be noted that, as used in this specification and the appended claims, the singular forms xe2x80x9caxe2x80x9d, xe2x80x9canxe2x80x9d and xe2x80x9cthexe2x80x9d include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to xe2x80x9ca reagentxe2x80x9d includes a mixture of two or more such reagents, and the like.
In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below.
xe2x80x9cAlkylxe2x80x9d is used herein to refer to a branched or unbranched saturated hydrocarbon group typically although not necessarily containing about 1-24 carbon atoms, unless indicated otherwise. Exemplary alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-amyl, isoamyl, n-hexyl, n-heptyl, n-octyl, n-decyl, hexyloctyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like, as well as cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and the like. Generally, although again not necessarily, alkyl groups herein contain about 1-12 carbon atoms. The term xe2x80x9clower alkylxe2x80x9d refers to an alkyl group of 1-6 carbon atoms, preferably 1-4 carbon atoms. In addition, the alkyl group can be substituted at one or more positions. Exemplary substituents include but are not limited to hydroxyl, boronic acid, cyano, alkoxy, xe2x95x90O, xe2x95x90S, xe2x80x94NO2, halo, heteroalkyl, amine, thioether, xe2x80x94SH, and aryl. Accordingly, if not otherwise indicated, the term xe2x80x9calkylxe2x80x9d includes linear, branched, unsubstituted, substituted, and/or heteroatom-containing alkyl groups. The term xe2x80x9ccycloalkylxe2x80x9d typically refers to a stable 3-to 7 membered monocyclic or 7-to 10-membered polycyclic ring which is saturated or partially unsaturated (e. g., containing one or more double bonds). Cycloheteroalkyls are cycloalkyls that contain one or more heteroatoms, and are typically stable 3-to 7 membered monocyclic or 7-to 10-membered polycyclic rings which are saturated or partially unsaturated and contain 1-4 heteroatoms (N, O, S, P or Si). Cycloalkyls and cycloheteroalkyls can be unsubstituted or substituted, where the substitutions can be on a carbon or a heteroatom if the resulting compound is stable. For example, any amino group contained within the heterocycloalkyl group can be a primary, secondary or tertiary amine, as long as the structure is stable.
xe2x80x9cArylxe2x80x9d is used herein to mean an aromatic substituent containing a single aromatic ring (e.g., phenyl) or multiple aromatic rings that are fused together (e.g., naphthyl or biphenyl), directly linked, or indirectly linked (such that the different aromatic rings are bound to a common group such as a methylene or ethylene moiety). Typically, the aryl group comprises from 5-14 carbon atoms. Preferred aryl groups contain one aromatic ring or two fused or linked aromatic rings, e.g., phenyl, naphthyl, biphenyl, diphenylether, diphenylamine, benzophenone, and the like. The aryl moiety may be independently substituted with one or more substituent groups, typically 1-3 substituents, including boronic acid, xe2x95x90O, xe2x80x94OH, xe2x80x94COOH, xe2x80x94CH2xe2x80x94SO2-phenyl, xe2x80x94C1-6alkyl, xe2x80x94Oxe2x80x94C1-6alkyl, xe2x80x94C(O)xe2x80x94C1-4alkyl, xe2x80x94(CH2)0-2xe2x80x94C(O)xe2x80x94Oxe2x80x94C1-4alkyl, cycloalkyl,xe2x80x94C1-6alkoxy, halo, nitro, amino, alkylamino, dialkylamino, xe2x80x94C(O)xe2x80x94N(C1-4alkyl)2, xe2x80x94NHxe2x80x94C(O)xe2x80x94C1-4alkyl, xe2x80x94C(O)xe2x80x94NH2, xe2x80x94SO2xe2x80x94NH2, trifluoromethyl, cyano, aryl, benzyl, xe2x80x94O-aryl and xe2x80x94S-aryl. Thus, the term xe2x80x9carylxe2x80x9d includes unsubstituted and substituted aryl groups. The term xe2x80x9cheteroarylxe2x80x9d refer to aryl, as defined above, in which at least one carbon atom, typically 1-3 carbon atoms, is replaced with a heteroatom (N, O, S, P or Si). The heteroaryl can have the heteroatoms within a single ring, (e.g., such as pyridyl, imidazolyl, thiazolyl, pyrimidine, oxazolyl, and the like), or within two rings (e.g., indolyl, quinolinyl, benzofuranyl, and the like). As with aryl, the term xe2x80x9cheteroarylxe2x80x9d is intended to include both unsubstituted and substituted heteroaryl groups. The substitutions can be on a carbon or a heteroatom if the resulting compound is stable. For example, any amino group contained within the heteroaryl group can be a primary, secondary or tertiary amine, as long as the structure is stable.
xe2x80x9cSilylxe2x80x9d is used herein to mean a silyl group (xe2x80x94SiH3) or derivative thereof. The term silyl can thus be represented by the formula xe2x80x94SiR3, where each R group is independently H, alkyl, cycloalkyl, cycloheteroalkyl, aryl or heteroaryl, an example of which is trimethylsilyl.
In its simplest form, the poly(aniline 3-boronic acid) (PABA) 6 precursor is readily synthesized by electrochemical polymerization of 3-aminophenylboronic acid in the presence of fluoride, as shown in Example 1.
Electrochemical methodologies are described in Shoji, et al., J. Am. Chem. Soc. 123:3383-3384 (2001) and Nicolas, et al., Eur. J. Org. Chem. 9:1703-1710 (2000), while the actual PABA synthesis is described in Valeur, et al., J. Phys. Chem. 96:6545-6549 (1992). The resulting poly(aniline 3-boronic acid) polymer exhibits conductivities and redox behavior similar to those of poly(aniline). In addition, the boronic acid groups remain reactive, providing a chemical handle for further transformations. Substituted poly(aniline 3-boronic acid)s 6a can be similarly synthesized.
Since the product is a polymer, it is understood that the poly(aniline boronic acid) precursor can also be poly(aniline 2-boronic acid), and will ultimately provide the same polymeric backbone. Accordingly, as used herein, the term poly(aniline boronic acid) is intended to mean poly(aniline 2-boronic acid) and poly(aniline 3-boronic acid).
Accordingly, one embodiment of the invention relates to a method of synthesizing a substituted poly(aniline) by reacting poly(aniline boronic acid) (optionally substituted with Ra, Rb and Rc) with a reagent to produce a substituted poly(aniline) of formula I.
In formula I, n is an integer within the range of about 1-10,000,000, preferably within the range of about 3-5,000,000, and more preferably within the range of about 3-1,000,000. The Z substituent is produced by the reaction (e.g., oxidation, substitution, coupling) of the reagent and the boronic acid substituent.
In a preferred embodiment, the substituted aniline is a polymer (n greater than 3). However, the invention also contemplates the synthesis of monomer substituted anilines (n=1) and dimer substituted anilines (n=2).
In another embodiment of the invention, each aniline has the same Z substituent. However, the methods of the invention also find utility in synthesizing poly(aniline)s where at least one of the Z substituents is boronic acid. This boronic acid-containing poly(aniline) is produced when the reaction is conducted so as to be an incomplete reaction, thus allowing some boronic acid substituents in the poly(aniline boronic acid) starting material to undergo an oxidation, substitution or cross-coupling reaction, while other boronic acid substituents remain unchanged. These remaining boronic acid substituents are particularly useful as cross-linking sites should it be desirable to cross-link the resulting polymer of formula I.
Accordingly, in one embodiment of the invention, a substituted poly(aniline) is synthesized by reacting poly(aniline boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; stopping the reaction before all of the boronic acid substituents in the poly(aniline boronic acid) undergo oxidation, substitution or cross-coupling; to produce a substituted poly(aniline) of formula Ixe2x80x2:
where n, Ra, Rb and Rc are as defined above; and wherein each Zxe2x80x2 is independently selected from the group consisting of xe2x80x94B(OH)2 and substituents produced by the reaction of the reagent and the boronic acid substituent, with the proviso that at least one Zxe2x80x2 substituent is a substituent produced by the reaction of the reagent and the boronic acid substituent.
The methods also find utility in synthesizing poly(aniline)s where the Z substituents are varied. In this manner, each substituted aniline monomeric unit contains a Z substituent that may be the same or different from the Z substituent present in the adjacent monomeric unit. For example, after the forced termination of the transformation of boronic groups to Z with a specific reagent A, the leftover boronic groups can be converted to other Z groups with a different reagent B. Alternately, each boronic group can be converted to a different substituent group in the presence of different reagents. In this case, each substituent group is specifically produced from its respective reagent.
Accordingly, in another embodiment of the invention, a substituted poly(aniline) is synthesized by reacting poly(aniline boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; to produce a substituted poly(aniline) of formula I, where n, Ra, Rb and Rc are as defined above; and wherein each Z is the same or different and is a substituent produced by the reaction of the reagent and the boronic acid substituent.
Exemplary reagents include, by way of illustration and not limitation, oxidation reagents, ipso-substitution reagents, and cross-coupling reagents. These reagents can be either electrophilic or nucleophilic reagents, and some reagents may be classified under several categories. For example, Br2 can functions as both an oxidation reagent and as an ipso-halogenation reagent.
Exemplary oxidation reactants include, by way of illustration and not limitation, peroxide.
Exemplary ipso-substitution reagents include, by way of illustration and not limitation, ipso-halogenation reagents, HgCl2, and ipso-nitration reagents. Examples of ipso-halogenation reagents include molecular halogen. Examples of ipso-nitration reagents include NH4NO3.
Exemplary cross-coupling reagents include, by way of illustration and not limitation, R1xe2x80x94SH, where R1 is selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; R2xe2x80x94Cxe2x89xa1Cxe2x80x94R3, where R2 and R3 are independently selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; R4xe2x80x94C(O)-thiophenyl, where R4 is selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; Suzuki cross-coupling reagents (e.g., R5 substituted, halo-substituted benzene, where R5 is selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl); and HOxe2x80x94C(R5)(R6)xe2x80x94C(R7)(R8)xe2x80x94OH, where R5, R6, R7 and R8 are independently selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl.
As noted in the background section, (hydroxyaniline) 4 is produced by the oxidative polymerization of its monomer. However, a variety of products is ultimately produced due to undesirable side-reactions. By using PABA 6 as the starting material, it is now possible to generate 4 exclusively in the presence of peroxide.
Accordingly, one embodiment of the invention relates to a method of synthesizing a hydroxy-substituted poly(aniline) by reacting poly(aniline 3-boronic acid) 6 with an oxidation reagent such as peroxide to produce a compound of formula Ia, where n is as defined above (formula Ia=formula I where Z is xe2x80x94OH). This is illustrated in the following Scheme Ia and in Example 2:
Details of this hydroxylation reaction, as well as those described below can be found in the references noted for Schemes 1-9.
Another embodiment of the invention relates to an ipso-halogenation reaction, whereby poly(aniline 3-boronic acid) 6 is reacted with molecular halogen (e.g., Cl2, Br2 or I2) to produce a halo-substituted poly(aniline) of formula Ib, where n is as defined above (formula Ib=formula I where Z is a halo group such as xe2x80x94Cl, xe2x80x94Br or xe2x80x94I). This is illustrated in the following Scheme Ib and Examples 2 and 3:
Scheme Ib is a significant advancement in the art since halogen-substituted poly(aniline)s Ib are difficult to synthesize using standard approaches, as noted in the background section. By using the poly(aniline 3-boronic acid) 6 of the invention, a range of halogenated poly(aniline)s Ib can be formed simply by exposing 6 to the corresponding molecular halogen in solution.
The invention also provides a coupling reaction for the synthesis of a thiol-substituted poly(aniline) by reacting poly(aniline 3-boronic acid) 6 with a thiol-containing compound (R1xe2x80x94SH) to produce a compound of formula Ic (formula I where n is as defined above, and Z is xe2x80x94SR1,
where R1 is selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl. This reaction is illustrated in the following Scheme Ic:
Another embodiment of the invention relates to a trans-metallation reaction, whereby poly(aniline 3-boronic acid) 6 is reacted with HgCl2 to produce an HgCl-substituted poly(aniline) of formula Id, where n is as defined above (formula Id=formula I where Z is xe2x80x94HgCl). This is illustrated in the following Scheme Id:
Another embodiment of the invention relates to a thioalkyne cross-coupling reaction, whereby a substituted poly(aniline) is prepared by reacting poly(aniline 3-boronic acid) 6 with a cross-coupling thioalkyne reagent of the formula R2xe2x80x94Cxe2x89xa1Cxe2x80x94R3, where R2xe2x80x94Cxe2x89xa1Cxe2x80x94R3, where R2 and R3 are independently selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl. The product is an alkyne-substituted poly(aniline) of formula Ie, where n is as defined above (formula Ie=formula I where Z is xe2x80x94Cxe2x89xa1Cxe2x80x94R3). This reaction is illustrated in the following Scheme Ie:
Another embodiment of the invention relates to a cross-coupling reaction, where poly(aniline 3-boronic acid) 6 is reacted with a cross-coupling thiol ester reagent to produce a carbonyl-substituted poly(aniline) of formula If, where n is as defined above (formula If-formula I where Z is xe2x80x94C(O)xe2x80x94R4, where R4 is selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl. This is illustrated in the following Scheme If:
The invention also provides for a Suzuki cross-coupling reaction., whereby a substituted poly(aniline) is produced by reacting poly(aniline 3-boronic acid) 6 with a Suzuki cross-coupling reagent such as an R5 substituted, halo-substituted benzene, where the halo group (X) can be chloro, bromo or iodo; and R5 is selected from the group consisting of xe2x80x94H, xe2x80x94B(OH)2, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl. The product is an aromatic-substituted poly(aniline) of formula Ig, where n is as defined above (formula Ig=formula I where Z is xe2x80x94C6H5xe2x80x94R5). This is illustrated in the following Scheme Ig:
The invention also provides for a cyclic boron group as a protection group or as a possible precursor to an anionic boronate group, for the synthesis of organoborane compounds. Poly(aniline 3-boronic acid) 6 is reacted with HOxe2x80x94C(CH3)2xe2x80x94C(CH3)2xe2x80x94OH to produce a borane-substituted poly(aniline) of formula Ih, where n is as defined above (formula Ih=formula I where Z is a boron ester. An exemplary reagent is HOxe2x80x94C(CH3)2xe2x80x94C(CH3)2xe2x80x94OH, as illustrated in the following Scheme Ih:
Another embodiment of the invention relates to an ipso-nitration reaction, whereby a substituted poly(aniline) is prepared by reacting poly(aniline 3-boronic acid) 6 with an ipso-nitration reagent such as ammonium nitrate to produce a nitro-substituted poly(aniline) of formula Ii, where n is as defined above (formula Ii=formula I where Z is xe2x80x94NO2. This is illustrated in the following Scheme Ii:
The reactions illustrated in Schemes Ia-Ii are intended to be illustrative only, and represent just a few of the many possible reactions accessible through the boronic acid group present in the poly(aniline boronic acid) precursor. One of skill in the art will readily appreciate that this precursor can be used in a variety of reactions to produce substituted poly(aniline)s. Schemes Ia-Ii illustrate poly(aniline)s that are substituted at the three position, since the poly(aniline boronic acid) exemplified is poly(aniline 3-boronic acid). It is understood that 2-substituted poly(aniline)s are obtainable in the same manner, using the poly(aniline 2-boronic acid) precursor. Further, Schemes Ia-Ii illustrate poly(aniline)s having hydrogen as the Ra, Rb and Rc substituents. This is not intended to be limiting in any manner and poly(aniline)s having other Ra, Rb and Rc substituents can be readily synthesized by techniques that are known in the art.


The present invention provides a method for improving the loading of nucleic acid on a solid support by contacting the solid support with a poloxamer-containing reagent. The present invention also provides a method for improving the stability of a nucleic acid on a solid support, comprising contacting a nucleic acid molecule with a partially double-strand oligonucleotide before or after loading the nucleic acid molecule on a solid support, so as to cause the nucleic acid molecule to hybridize with the oligonucleotide. The present invention also provides a combined use of the two methods.

Large-scale genomic sequence analysis is a key step in understanding many different biological phenomena. The need for low-cost, high-throughput sequencing and resequencing has enabled the development of new sequencing methods for simultaneous and parallel analysis of multiple nucleic acid targets.
In various sequencing methods, it is often necessary to load a nucleic acid target to be sequenced on a solid support. However, in conventional sequencing methods, there are many problems in loading a nucleic acid on a solid support, such as poor loading uniformity and poor stability of nucleic acid after loading.
Therefore, there is a need for an improved method to promote the uniform and stable loading of a nucleic acid on a solid support.

Method for improving loading and stability of nucleic acid


The present disclosure provides instruments, modules and methods for improved detection of edited cells following nucleic acid-guided nuclease genome editing. The disclosure provides improved automated instruments that perform methods—including high throughput methods—for screening cells that have been subjected to editing and identifying cells that have been properly edited.

In the following discussion certain articles and methods will be described for background and introductory purposes. Nothing contained herein is to be construed as an "admission" of prior art. Applicant expressly reserves the right to demonstrate, where appropriate, that the methods referenced herein do not constitute prior art under the applicable statutory provisions.
The ability to make precise, targeted changes to the genome of living cells has been a long-standing goal in biomedical research and development. Recently, various nucleases have been identified that allow for manipulation of gene sequences, and hence gene function. The nucleases include nucleic acid-guided nucleases, which enable researchers to generate permanent edits in live cells. Current protocols employing nucleic acid-guided nuclease systems typically utilize constitutively-expressed nuclease components to drive high efficiency editing. However, in pooled or multiplex formats constitutive expression of editing components can lead to rapid depletion of edited cell types and selective enrichment of cells that have not been edited. This occurs in most cell types because only a small fraction (<1-5%) of cells survive the introduction of double-strand DNA (dsDNA) breaks and thus these cells contribute fewer numbers to viable cell counts in the resulting populations compared to unedited cells that did not experience a dsDNA break.
There is thus a need in the art of nucleic acid-guided nuclease gene editing for improved instruments, modules and methods for creating genome edits and for identifying and enriching cells that have been edited. The present invention satisfies this need.

This patent is subject to a terminal disclaimer.

Instruments, modules, and methods for improved detection of edited sequences in live cells


A sealing blade includes opposite elongated edges (30, 31) and between them a flat (32) and which is adaptable to a blade holder (17) arranged in a coating applicator (25) of a coating device (21) and into contact with a moving surface (11′). The sealing blade has a contact surface (33), which may be arranged against the moving surface and which is 5-15% of the width (W) of the sealing blade (10).

The invention relates to a sealing blade, which includes opposite elongated edges and between them a flat and which is mountable to a blade holder arranged in a coating applicator of a coating device, where the sealing blade is brought into contact with a moving surface.
The coating or surface sizing of paper or board may be performed for example using a film transfer coater. In it, the web to be treated runs through a nip located between two rolls. The coating mixture or sizing agent is spread using a specific coating applicator onto the surface of one roll or both rolls, from which surface it is transferred onto the surface of the web to be treated in the nip between the rolls. The thickness and profile of the sizing agent layer on the surface of the roll may be adjusted for example by means of a doctor blade or a rotating metering rod.
The coating applicator may comprise an application chamber, which is limited in the direction of rotation of the roll by a doctor element and on the other hand by a front wall. In the lateral direction, the application chamber is limited by side seals. The coating mixture or surface sizing agent is fed into the application chamber for example through a channel located in a girder of the coating applicator. The coating mixture is fed into the application chamber at such a great speed and pressure that a return flow is created in the gap between the front wall and the application roll, in other words a coating mixture flow or sizing agent flow in a direction opposite to the direction of rotation of the application roll is created. The purpose of the return flow is to prevent the penetration of air, which is on the surface of the application roll, into the application chamber. If air can enter the application chamber, places with no coating may be created in the web.
It is well known that a sealing blade may be used as the front wall that closes the application chamber. The sealing blade may be pressed against the application roll so that no air escapes from between the blade and the application roll into the application chamber. There is no actual return flow from between the sealing blade and the application roll, but some coating mixture is led from the application chamber to the front of the blade through flow openings in the sealing blade. In this case, a pool of lubricant is formed in front of the sealing blade, which pool of lubricant prevents the friction occurring between the sealing blade and the application roll from damaging the roll or the sealing blade. If the pressure of the application chamber rises for example as a result of an excessive feeding of coating mixture, the force that presses the sealing blade against the application roll increases, whereby the sealing blade wears more rapidly and may damage the application roll or at least wear it.
However, a drawback related to the prior art sealing blade is that the edge of the blade placed against the application roll becomes sharp in connection with the use of the blade. This causes occupational safety problems in the maintenance of the coating applicator. A sharpened sealing blade is dangerous to the maintenance personnel for example when the sealing blade, metering rod or the cradle of the metering rod is replaced. For the replacement of just the metering rod and its cradle, which replacement needs to be performed in some cases more frequently than the replacement of the sealing blade, it is not often customary to remove the sealing blade from the coating applicator, because this is troublesome to perform. What makes the removal of the sealing blade difficult is that it may be firmly stuck to its blade holder and would therefore require washing to facilitate the removal. A sealing blade which has become sharpened and which is also difficult to remove may cause incised wounds to employees and also damage to the surface of the application roll.
Attempts in many different ways have been made to solve the problem related to the sealing blade becoming sharpened, but with little success. Since the holder of the sealing blade is fastened to the girder in a stationary manner, it is difficult to change the position of the holder. The sealing blade may also be lifted higher in the blade holder, but this does not always give the desired outcome, either. An attempt to enhance the lubrication that decreases the friction between the sealing blade and the application roll may be made by changing the feed pressure, but this is restricted by the seals that do not seal sufficiently well and by fouling problems. Moreover, it is not desirable to shift to a thinner sealing blade and a higher chamber pressure because of reasons such as increased leaks and splashes.
One prior art sealing blade that can be mentioned is in FI patent number 103058. The sealing blade known from it is a planar item. Both flat surfaces of the blade are hence essentially similar planar surfaces, in other words the front edge and the back edge of the blade are in the same plane.

Folded sealing blade for a coating applicator


The present invention is related to a device for influencing the flow in the region of a tube support plate (700, 800) of a tube bundle heat exchanger (100), for the food and beverage industry in particular. A displacement body (10, 11) is provided with a shank part (10c, 11c) which extends in the direction of its axis of symmetry (S) and which, at its end distal to the displacement body (10, 11) is fixedly connected to a connection bend (1000) or connection fitting (1100; 1200) which follows the exchanger flange (500; 1100e) or the connecting piece (800d).

The present invention is related to a device for influencing the flow in the region of a tube support plate of a tube bundle heat exchanger, for the food and beverage industry in particular, with an outer channel for a heat carrier medium surrounded by an outer shell, with a number of inner tubes which extend axis parallel to the outer shell through the outer channel, forming combinedly an inner channel and being supported in the tube support plate at their respective end sides, with an inlet or outlet common to all the inner tubes, formed in an exchanger flange; and with a common outlet or inlet for a product formed in a connecting piece, and with at least one displacement body influencing the flow in the region of the tube support plate, which is fixedly fastened and which is arranged axially symmetric and concentric to the tube support plate, formed by two portions which form a greatest common exterior diameter at their connecting cross section, with the displacement body, which axially symmetrically divides the flow to or from the inner channel, deflects it towards the outside and by doing so accelerates it in an annular gap cross section which is nozzle-like constricted between the displacement body and an inner contour of the exchanger flange and the connecting piece, respectively, and which subsequently forms an enlarging annular gap cross section together with the inner contour.
A device of this generic kind is known from DE 103 11 529 B3, the entire contents of which is incorporated herein by reference, or from WO 2004/083761 A1, the entire contents of which is incorporated herein by reference. The tube bundle heat exchanger to be considered is described in DE-U-94 03 913, the entire contents of which is incorporated herein by reference. A more recent state of the art relating to this, which is, however, in principle not different from the ancient state of the art, is described in the manufacturer's pamphlet "Röhrenwärmetauscher VARITUBE®" from GEA Tuchenhagen, Liquid Processing Division, 632d-00, of the year 2000, the entire contents of which is incorporated herein by reference.
Because of their cross section geometry, such tube bundle heat exchangers are generally better suited than other constructions of heat exchangers, like plate heat exchangers for instance, for the thermal treatment of products with high and low viscosities, of solid-containing products with whole pieces, pulp or fibres. All the same, even in this it is observed that deposits are formed on the inlet openings of the inner tubes of the tube support plates with fibrous media, like juices with fruit pulp. The treatment at relatively high temperatures favours the agglomeration of fibres and the formation of pulp. These are preferably deposited on the bridges between the multiple parallel arranged inner tubes and on the flat areas of the tube support plate, which are disposed across to the flow direction, and can lead to clogging there. Temporary deposits are released at intervals and the lumps reach the package of the respective product which is designated for the consumer, where they are undesirable and have to be avoided in every case.
The problem described above is resolved in a very satisfying manner by an apparatus proposed in DE 103 11 529 B3, the entire contents of which is incorporated herein by reference, or WO 2004/083761 A1, the entire contents of which is incorporated herein by reference, but only when an active central tube in the centre of the tube support plate can be omitted or is omitted in tube bundle heat exchangers which are to be built new, in order to permit the displacement body to have a fixed, unmovable connection with the tube support plate at this central location. Geometrically optimal tube pitches with 7, 19, 37 and more tubes, which all contain an active central tube, are not possible in this case. Thus, an optimization of the hydraulic design of tube bundle heat exchangers resulting from these so-called tube area pitches must be renounced up to now when the displacement body is to be fixed in the centre of the tube support plate as envisioned in the anterior state of the art.
Furthermore, for back fitting the tube support plate of any tube area pitch what so ever (with or without active central tube) with a displacement body of the kind in discussion here, it is proposed in the anterior state of the art to realise the displacement body as a sphere which is positioned freely movable in front of the tube support plate. Such a sphere is subject to a certain wear, which has to be considered to be hygienically objectionable in sensitive fields of the food and beverage industry.
It is the objective of the present invention to develop further an apparatus of the generic kind, avoiding solutions which are problematic in the hygienic, cleanability and fluid dynamic aspects, such that deposits from solid-containing products in the critical region of the tube support plate are still prevented, without that the latter is subject to limitations in view of desirable tube area pitches, and that simple back fitting of existing tube bundle heat exchangers with a fluidically effective displacement body is possible in addition, without the disadvantages which are hitherto known.

Device for influencing the flow in the region of a tube support plate of a tube bundle heat exchanger


A lawn mower for use both as walking operator type and riding type, having a grass cutting unit, an engine located rearwardly thereof, a driver's seat located above the engine, a floor step located over the grass cutting unit to be movable between an open position and a closed position, and right and left rear wheels driven by the engine. The rear wheels have respective stepless transmissions operable independently of each other to transmit engine drive in different speeds to the rear wheels. These transmissions are operable by shift levers located on opposite sides of the driver's seat when the lawn mower is used as the riding type, and by control levers extending rearwardly of the driver's seat when the lawn mower is used as the walking operator type.

1. Field of the Invention
The present invention relates to a lawn mower controllable by a driver riding the mower or walking behind the mower.
2. Description of the Related Art
A riding type lawn mower, as disclosed in U.S. Pat. No. 4,957,183, has an engine mounted on a front portion of a vehicle body, a driver's section disposed rearwardly, and a grass cutting unit underslung between front and rear wheels. The mower runs on the wheels driven respectively by hydraulic motors, and is steerable by turning the wheels up to about 90 degrees with a steering wheel disposed in the center and forwardly of a driver's seat.
The riding type lawn mower having the above construction is capable of a small, sharp turn with the center of turning moved to a position inwardly of a peripheral edge of the grass cutting unit. This turning capability provides the advantage of realizing an efficient grass cutting operation leaving no uncut patches. However, since the engine is mounted forwardly of the driver's section, the mower has an extensive fore and aft length. Consequently, the driver has difficulties in observing grass patches ahead of the mower during a grass cutting run. In addition, when boarding and alighting from the mower, the driver has the inconvenience of having to move through a narrow space between the driver's seat and steering wheel.
In the case of walking operator type lawn mower, one known example, as disclosed in U.S. Pat. No. 4,934,989, has a grass cutting unit mounted between caster type front wheels and engine-driven rear wheels, and control levers extending rearwardly for a walking operator to steer the mower. This lawn mower is easily controllable by operating transmission clutches provided for the rear wheels, respectively. It is possible to drive the mower along a complicated curve to engage in a grass cutting operation. However, when the mower i s caused to run along a long straight line, the operator must follow the mower in a tedious walk. The walking operator type lawn mower has a low reputation for use in an operation involving such long straight walks.

Lawn mower for use both as riding and walking operator type


A Software Defined Network (SDN) controller monitors load of Virtual FireWall (vFW) nodes in a firewall cluster in real time. When detecting that load of one or more vFW nodes is higher than a predefined first threshold, the SDN controller creates a new vFW node. The SDN controller selects a first flow, which is to be migrated, from flows passing through the monitored vFW nodes, updates a first flow entry corresponding to the first flow, and sends the updated first flow entry to a switch. The updated first flow entry indicates the switch to send the first flow to the new vFW node.

A Software Defined Network (SDN) is a new network structure. The core technology of the SDN is OpenFlow, which can implement flexible management of network flows by separating the control plane of a network device from the data plane of the network device.
A SDN controller may implement functions including the collection of network topology, the calculation of routing, the generation and distribution of flowentries, the management and control of a network. A network layer device may perform the forwarding of flows and the execution of policies.
Network Functions Virtualization (NFV) is an Industry Specification Group (ISG) of European Telecommunication Standards Institute (ETSI). In a NFV method, all kinds of network elements become separated applications, and may be deployed flexibly on a platform that is constructed based on standard servers, storages and switches.
NFV technology is based on cloud calculation and virtualization technology. A universal Commercial Off-The-Shelf (COTS) calculation/storage/network hardware device may be divided into many kinds of resources by the virtualization technology, so as to be used by various applications in an upper layer. Further, the applications may be decoupled from hardware, thereby greatly improving the supply speed of resources.
By a firewall stack technology, multiple physical firewall devices may be stacked to form a logic firewall device.


A compound semiconductor radiation detector includes a body of compound semiconducting material having an electrode on at least one surface thereof. The electrode includes a layer of a compound of a first element and a second element. The first element is platinum and the second element includes at least one of the following: chromium, cobalt, gallium, germanium, indium, molybdenum, nickel, palladium, ruthenium, silicon, silver, tantalum, titanium, tungsten, vanadium, zirconium, manganese, iron, magnesium, copper, tin, or gold. The layer can further include sublayers, each of which is made from a different one of the second elements and platinum as the first element.

1. Field of the Invention
The present invention relates to semiconductor radiation detectors and, more particularly, to the configuration of an electrode formed on at least one surface of the semiconductor radiation detector.
2. Description of Related Art
Cathode electrodes and anode electrodes of Cadmium Zinc Telluride (CZT) radiation detectors are presently formed of platinum thin films. The platinum forming each electrode is deposited via a suitable thin film deposition technique, such as, without limitation, sputtering, to a thickness of approximately 1000 angstroms. However, this thickness is not to be construed in a limiting sense.
Each platinum electrode defines an electronic contact that enables the CZT bulk material to have superior performance when acting as an x-ray or gamma-ray radiation detector and to interface with electronics with sufficient connectivity to allow for data acquisition and control electronics to form a functional and high performance CZT detector based sensor.
In the case of a CZT detector based sensor system, platinum electrodes provide for the proper work function and chemical bond to the CZT bulk material such that the work function matches the CZT bulk material's bandgap, resistivity, and interface electronic properties, thereby enabling the CZT bulk material, or other suitable compound semiconductor crystal material, to realize full depletion of the entire CZT bulk material volume with excellent collection of charge carriers generated by the absorbed x-rays and gamma rays. The high sensitivity provided by the full depletion of the entire CZT bulk material volume and the good charge collection ensures nearly loss free signal generation from absorbed photons and provides higher performance levels of CZT based detectors than many other semiconductor detectors.
In the manufacture of compound semiconductor devices, such as CZT detectors, the mechanical fragility of the delicate thin platinum electrode metal prohibits the use of robust manufacture methods to fabricate these devices. Specifically, after deposition, the delicate thin-film platinum electrodes are easily damaged during subsequent device fabrication steps such as, without limitation: in-line probe testing; device handling during downstream device processing; and bonding to interconnect substrates or read-out electronics during integration to signal processing electronics.
One means of compensation for the fragility of thin platinum electrodes involves the subsequent deposition of an excessively thick second pure metal layer (typically gold) using a suitable thick film deposition technique and, if desired, a third pure metal layer (typically vanadium) using a suitable thick film deposition technique to protect the underlying platinum layer and provide a (deformable) buffer layer between the underlying platinum layer and probe contacts, bonding bumps, in-line device handling tools, and the like. The application of one or more excessively thick film metal layers, however, is impractical and costly with thin-film equipment, whereupon this approach requires the implementation of alternative thick-film deposition processes into the CZT detector fabrication process. With excessive film thickness, however, there is also the confounding relationship that film conformality to its substrate is reduced, thus resulting in the potential for electrodes to delaminate from the underlying surface. Excessive electrode thickness is also not desirous from a device reliability perspective.
The current state of the art in the fabrication of CZT detectors, and other compound semiconductor devices, has not produced devices with acceptably robust electrode structures which are capable of being mechanically probed prior to bonding of device pixel and full-area electrodes to interconnect substrates or read-out electronics. Existing CZT detectors are frequently damaged when probed in-process, thus requiring repeated and excessive processing to allow for such processing. An illustration of induced pin-probe damage on prior art platinum electrodes is shown in FIGS. 1A and 1B.
The performance and cost of CZT detectors, and other compound semiconductor devices, would greatly benefit from in-process probe testing thereof before proceeding further in the manufacturing cycle. This would provide for opportunities to improve production efficiency and reduce manufacturing costs for the fabrication of these detectors. For example, knowing ahead of the completed/mounted CZT detector manufacture that the CZT detector is either functional, non-functional, or partially functional, would enable decisions to be made to further process, reject, or selectively bin the CZT detector by quality level for subsequent final device manufacture disposition, respectively.
After deposition on a CZT detector, platinum electrodes are soft and frequently scratched during subsequent handling and manufacture of CZT detectors into radiation detectors. Even minor scratching of these delicate platinum electrodes can cause damage to the underlying CZT-to-metal interface and the generation of electronic noise in use of the CZT detector. At a minimum, this damage can deteriorate the performance and reduce the operability range (bias voltage, temperature) of the CZT detector. Often this damage is catastrophic and renders the CZT detector unusable for its intended application. When scratched, a CZT detector may require rework, re-metallization, or may be lost as scrap. Often the weight of a CZT detector on a so-called clean room wipe is all that is required to damage these delicate platinum electrodes alone or platinum electrodes having one or more suitable overlayers, such as, without limitation, a gold overlayer, or the combination of gold and vanadium overlayers.
Another area where more robust platinum electrodes would greatly improve fabrication yields and the short and long-term reliability of CZT detectors is during the bonding of the CZT detectors to interconnect substrates or read-out electronics. Typically, some form of flip-chip bonding is used to integrate CZT detectors to readout electronics (e.g., conductive epoxy bump bonding, low temperature solder bonding, gold stud bonding, ball-grid arrays, unidirectional conductive epoxy bonding and the like). All of these interconnect technologies employ dissimilar materials and wide curing/processing temperature cycles to achieve the required electrode/pixel connectivity. Thermo-mechanical stresses induced during the bonding process and long-term mechanical fatigue as a result of thermal cycles are the two main causes of connectivity failure. In case of delicate compound semiconductors, such as CZT, metal film damage can occur to the semiconductor-to-metal interface of a platinum electrode during both the bonding process, as a result of applied forces and thermo-mechanical stresses, and in the field during use due to thermal cycling induced interface fatigue and failure.
Hardening the platinum electrodes or multi-layer electrode described above would reduce device failure during the bonding process and improve the long-term reliability of the CZT detector in the field. Moreover, a hardened platinum layer by itself or in combination with a second and, if desired, a third layer would serve as a stress and strain barrier against mechanical deformation during the bonding process and subsequent use in the field while maintaining the favorable electrical properties of the barrier at the semiconductor-platinum interface.
However, common methods of work hardening, such as thermal processing to create tempering, are not permissible processes by which to improve electrode mechanical durability for many compound semiconductor crystals. For example, the detector material CZT is mechanically sensitive and work hardening is not a viable option for a platinum electrode of a CZT detector. CZT material is also thermally sensitive to temperatures above approximately 200° C. and such temperatures may not be employed as the device performance degrades due to thermally induced material changes. This eliminates bulk thermal processing as a method by which mechanical characteristics of the platinum may be improved.

Semiconductor radiation detector with thin film platinum alloyed electrode


Method for making a filter cartridge that is suitable for attachment to a respiratory mask. The method comprises the steps of (a) providing a mass of filter material; (b) providing a filter cartridge housing that has an inlet and outlet and a sidewall that includes sheet material; and (c) thermoforming the sheet material of the housing sidewall around at least part of the mass of filter material to place the housing sidewall in direct contact with the mass of filter material to encapsulate the filter material so that fluid is prevented from passing through the filter cartridge from the inlet to the outlet without being filtered by the mass of filter material.

A filter element often needs to be replaceable so that when it reaches the end of its useful life, it can be removed from the filtering apparatus in which it is used and can be replaced by a new filter element. Filter elements are commonly in the form of a cartridge, the housing of which may be provided with some form of attachment mechanism that enables the cartridge to be fitted in, and removed from, the filtering apparatus in which it is used. In other cases—for example, certain types of respiratory masks—the filtering apparatus is intended to be discarded when the filter element reaches the end of its useful life, and, in those cases, the filter element can be an integral part of the filtering apparatus.
Filter cartridges usually are assembled by first forming the housing and then inserting a filtering material into the housing—see, for example, U.S. Pat. Nos. 4,592,350, 5,063,926, 5,736,041, 6,277,178, and 6,248,280; and DE-A-197 00 340. As illustrated in some of these documents, the housing can be formed in two parts that are closed after the filtering material has been placed in position. Respiratory masks that have filter elements as integral parts of the masks have also been described, for example, in U.S. Pat. Nos. 2,922,417, 2,922,418, 3,861,381, and 4,790,306, and in EP-A-0 218 348.
Sorbent particles such as activated carbon are commonly used in respirators as gas or vapor filters. The filters generally are classified according to the manner in which the sorbent material is supported in the filter and include packed bed filters, loaded nonwoven filters, loaded foam filters, and bonded sorbent filters.
In packed bed filters, the sorbent particles are constrained in a container by compressive forces imposed on and transmitted through the particle bed by rigid grids and screens that cover the inlet and outlet areas. Packed bed filters tend to be cylindrical, have constant thickness or bed depth, and have a planar inlet and outlet. To fill the cartridge, the adsorbent particles typically are poured through screens that scatter the particles as they fall, creating a level bed packed substantially to maximum density. The compressive forces from the constraining grids and screens restrain particle movement to minimize flow channeling through the packed bed.
An example of a packed bed filter is shown in U.S. Pat. No. 4,543,112. This patent discloses a sorbent filter assembly made by sequentially placing a first resilient perforated plate, a first retention filter, a sorbent bed, a second retention filter, a second resilient perforated plate, and a cover within the cylindrical portion of a canister shell. The cover is forced downwardly to compress the sorbent bed and to resiliently spring bias or stress the first resilient perforated plate. While the parts are held together under compression, an annular edge portion of the cylindrical shell is rolled into a circumferentially extending groove on the canister cover to hermetically seal and mechanically hold the parts together in their assembled and compressed relationship.
The necessity for this number of parts and processing steps introduces complexity as well as weight, bulk, and cost. A further problem is experienced when a packed bed respirator is combined in series with a particulate filter for use in environments containing particulates as well as vapor hazards such as in paint spray applications. In this situation, the retaining grids and screens may create nonuniform airflow pathways within the particulate filter, resulting in reduced utilization of the filter media and increased pressure drop therethrough.
Loaded nonwoven webs that contain sorbent particles in the interstices between the fibers forming the web have been disclosed in the filtering face mask art. An example is shown in U.S. Pat. No. 3,971,373. Loaded foams also have been disclosed that contain adsorbent particles dispersed within and bonded in the foam structure. U.S. Pat. No. 4,046,939 describes a carbon impregnated foam for protective clothing against noxious chemicals. Both loaded nonwoven webs and loaded foam structures are edge sealed to the respirator component to prevent unfiltered air from bypassing the filter. Known sealing means include adhesives, such as disclosed in U.S. Pat. No. 5,063,926, and gaskets or sealing rings, such as disclosed in U.S. Pat. No. 5,222,488. Loaded structures generally suffer from having a lower sorbent particle density than the packed beds.
A significant advance over the packed beds technology and loaded webs and foams was the invention of bonded sorbents. In bonded sorbent technology, the sorbent particles are molded into a unitary structure using polymer particles that bind the sorbent particles together. Bonded sorbent structures eliminate the need for additional supporting structures, as are necessary in packed beds. An example of a bonded sorbent structure is disclosed in U.S. Pat. No. 5,033,465 (see also U.S. Pat. No. 6,391,429 B1). Bonded sorbent structures have been sealed to the respirator using an adhesive—see, for example, U.S. Pat. No. 5,078,132; or by injection molding—see, for example, U.S. Pat. No. 4,790,306.

Method of making a filter cartridge using a thermoforming step


A mobile telecommunications device runs a plurality of applications installed on the device (for providing services to the device user). Monitoring means monitors the performance of the applications for generating performance data (for each application), and analyzing means analyzes the performance data (for each application) and to identify characteristics of the applications in dependence thereon. The mobile device may alert a user of the device of the problematic ones of the applications (for example via the GUI of the device). A mobile telecommunications device application performance analyzing apparatus may be coupled to the mobile telecommunications network that provides mobile telecommunications services to a plurality of mobile telecommunications devices and may receive the performance data and which includes analysis means for conducting analysis of the performance data to identify characteristics of the applications in dependence thereon.

Surging data demand driven by the mobile devices mind-set of consumers, the proliferation of smartphones and onset of the use of applications ("apps") on mobile devices is revolutionising the mobile industry. In 2010, smartphones accounted for more than 30 percent of total wireless handset sales. The uptake in smartphone usage is mostly driven by mobile apps, which, while using Internet in the background, offer a personalised experience to the user. A study from the Pew Internet Project illustrates that one in four US adults use mobile apps. App users had an average of 18 apps on their devices and a median of 10, the study estimates.
However, due to the open nature of apps ecosystem, any developer can upload an application to the source of applications (e.g. Android Market or Apple's App store) without any quality assurance checks. This results in a large number of malicious applications making their way to smartphones that attempt to take advantage of user's proclivity to ignore permissions and other warning signs and install whatever looks good to them. Some of the apps are truly dangerous, while others are simply not well written—e.g. not optimised so that they consume excessively device battery power and/or the user's data allowance (such as by sending unnecessary traffic to the network).
Current methods of rating applications are typically very simplistic. Typically, applications are rated according to how many times they have been downloaded. This is not particularly useful to a user, as applications that are downloaded frequently, may be deleted shortly thereafter if they are unsatisfactory.
Today, an important proportion of returned smartphones is the result of problems with apps and software, rather than hardware. Moreover, in a smartphone dominated marketplace, the performance of mobile apps is regarded as an important component of network operator selection and customer loyalty. It would be advantageous to offer a capability to users to make informed decisions while downloading applications, monitor real time apps performance, control their privacy and properly manage the apps on their smartphones. Moreover, with a better visibility of customer's smartphones apps performance, network operators could take predictive customer actions (e.g to offer customers upgraded services) through product and channel intervention.
Raw data collection gathering software is known in the form of an application which a user can download on their smartphone (or may be pre-installed) that interacts with other applications running on the smartphone in real-time (in the background) and monitors their performance in terms of battery consumption, CPU usage, data consumption, user privacy settings and app experience (data rate, latency). However, although such an application can collect data, it does not use/analyse the data to improve the user experience or network performance, and nor does it offer a solution for monetising the data.
It is in theory possible for the core of a mobile telecommunications network to analyse data sent to/from mobile terminal applications but it is difficult to identify to which application data relates, and impracticable to identify traffic relating to a particular application relating and to a particular mobile device user. Analysis at the network core, even if possible, does not provide representative data of application use as about 80% of data traffic from mobile terminals is currently transmitted over WLAN radio access networks rather that cellular networks.


Location of an object to be tracked is determined by measuring, at a receiver situated at the object, the propagation time differences between the signals from a plurality of GPS satellites, each of which is received by the receiver situated at the object. The measured propagation time difference values are transmitted to a central station where the location of the object to be tracked is calculated based upon the propagation time differences of the signals transmitted from the satellites and data derived from a receiver apart from the object but also receiving signals from the satellites.

The tracking and location of assets such as railcars, shipping or cargo containers, trucks, truck trailers, automobiles, etc. can be highly advantageous in commerce. Precise tracking of such vehicles and objects can facilitate their being allocated and positioned in an efficient manner, and can provide for immediate, accurate localization of lost, delayed or damaged assets. The space-based global positioning system (GPS) implemented by the United States Department of Defense constitutes a convenient instrumentality for determining geographical position in real time.
The GPS is a multiple satellite-based radio positioning system in which each satellite transmits data that allows precise measurement of the distance from selected ones of the GPS satellites to the antenna of a user's receiver so as to enable the user to compute position, velocity and time parameters through known triangulation techniques. The signals provided by the GPS can be received both globally and continuously.
The GPS comprises three major segments known as the space, control and user segments. The space segment consists of 21 operational satellites and three spare satellites. The satellites are positioned in a constellation such that typically seven satellites, but a minimum of four, are observable by a user anywhere on or near the earth's surface. Each satellite transmits signals on two frequencies known as L1 (1575.42 MHz) and L2 (1227.6 MHz), using spread spectrum techniques that employ two types of spreading functions.
C/A (or coarse/acquisition code) and P (or precise) pseudo random noise (PRN) codes are transmitted on frequency L1, and P code only is transmitted on frequency L2. The C/A is available to any user, military or civilian, but the P code is only available to authorized military and civilian users. Both P and C/A codes contain data that enable a receiver to determine the range between a satellite and the user.
Superimposed on both the P and C/A codes is a navigation (NAV) message. A NAV message contains the GPS signal transmission time; a handover word used in connection with the transition from C/A to P code tracking; ephemeris data for the particular satellites being tracked; and almanac data for all of the satellites in the constellation, including information regarding satellite health, coefficients for the ionospheric delay model for C/A code users, and coefficients used to calculate universal coordinated time (UCT).
The control segment comprises a master control station (MCS) and a number of monitor stations. The monitor stations passively track all GPS satellites in view, collecting ranging data and satellite clock data from each satellite. This information is passed on to the MCS where the satellite's future ephemeris and clock drift are predicted. Updated ephemeris and clock data are uploaded to each satellite for retransmission in each satellite's navigation message. The purpose of the control segment is to ensure that the information transmitted from the satellite is as accurate as possible.
The GPS is intended to be used in a wide variety of applications, including space, air, sea and land vehicle navigation, precise positioning, time transfer, altitude referencing and surveying. A typical GPS receiver comprises a number of subsystems, including an antenna assembly, an RF (radio frequency) assembly, and a GPS processor assembly. The antenna assembly receives the L-band GPS signal and amplifies it prior to insertion into the RF assembly. A significant factor affecting accuracy of the computed position, velocity or time parameters is the positional geometry of the satellite selected from measurement of ranges. Generally, a best position solution is obtained using satellites having wide angles of separation. Considerable emphasis has therefore been placed on designing antenna systems to receive, with uniform gain, signals from any point on the hemisphere.
The RF assembly mixes the L-band GPS signal down to a convenient IF (intermediate frequency) signal. Using various known techniques, the PRN code modulating the L-band signal is tracked through code-correlation at the receiver. This provides the processing gain needed to achieve a signal-to-noise (SNR) sufficient for demodulating the navigation data and signal transmission time. The Doppler shift of the received L-band signal is also measured through a carrier tracking loop. The code correlation and carrier tracking function can be performed using either analog or digital signal processing.
By differencing the signal transmission time with the time of reception, as determined by the clock of the receiver, the pseudo range between the receiver and the satellite being tracked may be determined. The pseudo range includes both the range to the satellite and the offset of the clock from the GPS master time reference. The pseudo range and Doppler measurements (and the navigation data) from four satellites are used to compute a three dimensional position and velocity fix, which calibrates the receiver's clock offset and provides an indication of GPS time.
In some known receivers, the receiver processor controller (RPC) functions are performed using a computer separate from that on which the navigation functions are performed. In other known receivers, both types of functions are performed by a single computer. The RPC processing and memory functions performed by a typical GPS receiver include monitoring channel status and control, signal acquisition and reacquisition, code and carrier tracking loops, computing pseudo range (PR) and delta range (DR) measurements, determining data edge timing, acquisition and storage of almanac and ephemeris data broadcast by the satellites, processor control and timing, address and command decoding, timed interrupt generation, interrupt acknowledgment control and GPS timing.
U.S. Pat. No. 5,225,842 describes an apparatus and method for computing the position and velocity of multiple low cost vehicle-mounted sensors, monitored and tracked by a central control station. The receiver processor functions are physically separated from the navigation functions and the low rate data interfaces provided between the computers that perform these functions, thus achieving cost saving in the GPS sensor that is employed on board each vehicle.
One type of known GPS receiver is described in U.S. Pat. No. 4,114,155, wherein the position of a receiver responsive to C/A signals derived from multiple, orbiting spacecrafts is determined to an accuracy better than 300 meters. Each of the C/A signals has the same carrier frequency and a different, predetermined Gold code sequence that normally prevents position determination from being more accurate than to within 300 meters. C/A signals transmitted to the receiver are separately detected by cross-correlating received Gold code sequences with plural locally derived Gold code sequences. Four of the detected C/A signals are combined to compute receiver position to an accuracy of 300 meters. To determine receiver position to an accuracy better than 300 meters, the relative phase of internally-derived Gold code sequences is varied over the interval of one chip (i.e., pulse) of each sequence, to derive second cross-correlation values indicative of received and locally-derived Gold code sequences.
The basic approach followed most recently is to receive and process the signals from several of the GPS satellites in order to determine range to each satellite (and relative velocity). With perfect knowledge of range to only three of the GPS satellites, exact receiver position can be determined from the intersection of the three "spheres" induced by the known satellite positions and the derived receiver ranges. With receiver noise and imperfect knowledge of satellite positions, the receiver-satellite ranges can only be estimated. Typically, errors from receiver noise are reduced by (effectively) averaging many range calculations.
In the above most recent approach, the range from a particular satellite is estimated by reading a time stamp from the satellite's data stream (the transmission instant), subtracting this from the reception time, and multiplying the time difference by the speed of light. Any error in satellite and receiver clock synchronization leads to proportional range errors. Because the same clock is used in receiving from all satellites, there is only one unknown receiver clock "bias". By using a fourth (or more) satellite, the clock bias and ranges can be jointly estimated.
At the receiver, the reception time is determined by performing a cross-correlation of the received data with a local replica of the known satellite Gold code, and noting the time of a chosen correlation peak, and its position relative to the time stamp. The satellite signal structures use Code Division Multiple Access (CDMA) so that the above cross correlation is part of the standard GPS receiver processing.
The above-described system that follows the most recent basic approach assumes that each receiver must determine its own position. In the system of the invention, there is a central facility or station that needs the receiver positions and can communicate with the receivers. Each tracked object (e.g., a railcar) carries a GPS-based receiver that processes data from several of the visible GPS satellites. However, the full position determination is not made at the railcar. Instead, only partial processing is done at the railcar and intermediate results are transmitted to the central station. The forms of both the partial processing and intermediate results are chosen to minimize the complexity and energy requirements at the railcars.
The standard GPS system requires that the transmit-time stamps, satellite ephemeris and other correction data be decoded from each satellite's data stream at the tracked object. The receiver is thus required to process data from each satellite long enough (between six and 150 seconds) to synchronize with, and decode, these data. This consumes significant power.

Reduced-power GPS-based system for tracking multiple objects from a central location


A chitosan enhanced erosion control device is described. A walled elongated core member is disclosed having a first open end, a second end, an interior space and one or more openings in the wall communicating the interior space with the exterior of the core member. An outer filter member surrounds the core member. One or both the first and second ends of the core member can be open. One or both of the open ends can comprise couplers or connectors for connecting one core member to one or two complimentary core members. The core member may comprise a flexible plastic pipe, such as high-density polyethylene pipe having a plurality of perforations. Chitosan may be added to one or more device elements to assist in removing unwanted silt and contamination from passing fluid.

The present invention relates generally to erosion control and more particularly to devices and apparatuses for use in controlling pollution, silt, sedimentation and debris flow associated with soil erosion.
Controlling soil erosion, such as erosion on slopes in construction sites, and particularly the sedimentation and debris carried in fluid flow on slopes is a continuing problem. Fiber rolls (also known as wattles) are the current industry standard for use in controlling erosion. Fiber rolls are typically made of fibrous materials such as straw or excelsior (shredded wood) made into rolls that are held together with netting. During construction, the rolls are placed across the face of a slope to curtail soil erosion and to dam, direct and/or filter fluid flow as the fluid flows down the slope. Silt fences, generally black porous cloth strung vertically on wooden stakes across a slope, are alternative means of controlling erosion. However, most regulatory agencies now discourage the use of silt fences due to the propensity for silt fences to collapse from high fluid flows and high winds. Fiber rolls have been found to be more capable of performing the erosion control function than silt fences. However, fiber rolls are deficient in their ability to direct fluid flow in a controlled manner. Moreover, numerous fiber rolls are generally required due to their inherent deficiencies in directing fluid flow as the flow proceeds down a slope.
Furthermore, in response to tighter guidelines recently imposed by the federal Environmental Protection Agency under the Clean Water Act, controlling pollution and erosion from storm water runoff is receiving ever-increasing attention at all levels of government, federal, state and local. Federal and state agencies have issued mandates and developed guidelines regarding the prevention of non-point source (storm water caused) pollution that require local governments to act upon or initiate. These mandates also affect water runoff from storms and other sources on slopes and construction sites. Fiber rolls or xe2x80x9cwattlesxe2x80x9d have traditionally done a poor job of controlling or filtering pollution, debris or sediment from fluid flows, however, as water or runoff that flows from a fiber roll is typically substantially similar in nature to the water or runoff that flows into the fiber roll.
Chitosan is a well-known material that is derived from a naturally occurring substance called chitin, which is a polysaccharide found in the exoskeleton of shellfish such as shrimp, lobster, and/or crabs. While chitosan has recently gained popularity as a dietary supplement, its inherent ability to generate small electrical charges has also provided benefits in the processing of contaminated items, such as wastewater. In turbid or polluted water, the electrical charges given off by chitosan react with the small electrical charges in pollution, fine silt and sediment particles, such that many of these tiny bits of contamination and silt coagulate together into larger chunks. These larger coagulated chunks of particles can then be filtered more easily from the fluid and are also more prone to settle to the bottom of the fluid body via gravity. An appropriate application of chitosan can render a body of muddy water as fairly clear in a short period of time. While chitosan and chitin have been previously used to some extent in the treatment of wastewater, their use has yet to reach the field of storm water runoff with its accompanying objective to filter or clarify such water. Accordingly, more effective devices and systems are desired for controlling soil erosion and debris flow, and for filtering or clarifying fluid passing through such devices and systems.
The present invention comprises a walled elongated core member having a first open end, a second end, an interior space and one or more openings in the wall communicating the interior space with the exterior of the core member. An outer filter member surrounds the core member. In one embodiment, both the first and second ends of the core member are open. One feature of the present invention is the ability to connect a plurality of core members together. Accordingly, one or both of the open ends can comprise couplers or connectors for connecting one core member to one or two complimentary core members. The core member may comprise a flexible plastic pipe, such as high-density polyethylene pipe having a plurality of perforations.
In another embodiment, the couplers can comprise tee connectors or elbow connectors. One advantage of the present invention is the ability to connect outlet pipes to tee or elbow connectors for directing fluid flow received by the core members to desired locations downstream of the core members.
The outer filter member may comprise a fiber roll. In one embodiment the fiber roll comprises excelsior or straw. In another embodiment, the filter member may comprise a porous foam material. A porous covering material, such as a woven cloth or netting may surround the outer filter member.
In another embodiment, the elongated core member is corrugated, comprising a plurality of ribs extending along a least a portion of the exterior surface of the core member. One or more openings in the ribs communicate the interior of the core member with the exterior surface of the core member.
In another embodiment, the elongated core member comprises a flexible material have an interior space that is at least partially filled with a ballast material such as sand, gravel or the like. The elongated core member may further comprise openings communicating the exterior of the core member with the interior of the core member. One or more core members can be coupled together and strategically arranged to control the flow of sedimentation and debris.
In yet another embodiment, chitosan is applied to one or more parts of the fiber roll, preferably before the fiber roll is assembled. While a liquid form of chitosan is preferred, any other form, such as a powder, may be applied to the fiber roll. In the preferred embodiment, a liquid solution of chitosan is thoroughly sprayed onto a flat blanket comprising the outer filter member before this blanket is rolled around the elongated core member. This outer filter member preferably comprises excelsior, and is preferably left to dry for a period of time after the liquid solution is applied. Once assembled, the chitosan enhanced fiber roll is capable of coagulating fine solids in fluids, such that passage of pollution, silt and sediment through the fiber roll is reduced.


There is prepared a formed body constituted of steel and having an outer circumferential surface having an annular groove having a bottom surface to serve as a raceway surface of the bearing ring. In the step of forming a heated region, the formed body is induction heated to form a heated region including the bottom surface of the groove and heated to a temperature of at least an A1 point. In the cooling step, the whole of the heated region is simultaneously cooled to a temperature of not more than an Ms point. The step of retaining the formed body in a state in which heating is stopped is performed after the step of forming a heated region before the step of cooling. In the step of retaining, dispersion in temperature in the heated region in the circumferential direction is suppressed to not more than 20° C.

A bearing for a wind turbine generator, such as a main shaft bearing that supports a shaft transmitting a blade's rotational power, is acted on not only by a load component attributed to the weight of the blade and that of a rotor but also by a load component attributed to a wind load. That is, in addition to a radial load, an axial load also acts on the bearing. For this reason, it has been conventionally proposed to use a double row tapered roller bearing as a bearing for a wind power generator (see, for example, Japanese Patent National Publication No. 2008-546948).

Method for producing bearing ring, double row tapered roller bearing, and method for producing double row tapered roller bearing


A crank has a connection portion with a connection recess defined therein which has an engaging recess, a reception recess and a reception groove. The engaging recess is located at a closed end of the connection recess and the reception recess is located at an opened end of the connection recess. The reception groove is located between the engaging recess and the reception recess. An axle has an engaging portion at an end thereof and the engaging portion is engaged with the engaging recess. A guide surface is defined in an outer periphery of the cylindrical body. A ring-shaped washer is mounted to the cylindrical body and securely fills into the reception groove and the gap between the axle and the reception recess.

A conventional bicycle crank 10 is shown in FIG. 1 and generally includes a connection portion 11 through which a connection hole 12 is defined. A large-diameter groove 13 is defined in the inner periphery of the connection hole 12 and opens to the outside of the connection portion 11. The axle 14 has an end with an engaging portion 15 which has a larger diameter so as to be engaged with the groove 13. However, the end that has the engaging portion 15 is exposed to the outside of the connection portion 11 of the crank 10 so that dust, water can easily enter the opening 16 in the end of the axle 14. A cap 17 is then inserted into the opening 16 of the axle 14 to avoid the entry of the dust and water. However, the cap 17 obviously cannot make the crank 10 to be aesthetic as expected. And the cap 17 increases the cost.
FIG. 2 shows another bicycle crank 20 wherein the connection portion 21 has a connection hole 22 which is defined through the connection portion 21, and a flange 23 extends inward from the inner periphery of the connection hole 22. The axle 24 has its end contacting the inside of the flange 23 and a threaded hole 25 is defined in the end of the axle 24. A bolt 26 is threadedly connected to the threaded hole 25 to connect the axle 24 and the crank 20. However, the bolt 26 can be seen from outside of the crank 20. In addition, the threaded hole 25 and the bolt 26 increase the manufacturing cost of crank and the bolt 26 requires extra assembling step.
The present invention intends to provide the connection of a bicycle crank and an axle which is more secured to the crank and does not exposed from outside of the connection portion of the crank.


A model railroad car magnetic coupling and uncoupling system employs pairs of cooperating magnetic couplers that have unique and simplified constructions, and an uncoupler mechanism that is mounted beneath a section of model railroad track and operates automatically to separate the mechanical couplers of two adjacent model railroad cars positioned on the section of track.

(1) Field of the Invention
The present invention pertains to magnetic couplers that magnetically couple two adjacent model railroad cars positioned on a section of model railroad track, and an apparatus that selectively uncouples the two magnetically coupled model railroad cars.
(2) Description of the Related Art
In the hobby of model railroading there is a large group of enthusiasts that are interested in the collection, assembly and operation of smaller sized or smaller scaled model railroad layouts. Be it a desire for a model railroad layout that does not require a large expanse of space, or the challenge of assembling a realistic looking model railroad layout in a smaller scale or size, in recent years the trend in model railroading has been toward the increasing popularity of smaller and smaller scales or sizes. A first popular scale was the "O" scale, or 1:48 scale. Then came the "HO" scale, or the 1:87 scale. This was followed by the "N" scale or 1:160 scale, which was followed by the "Z" scale, or 1:220 scale.
Although the trend in model railroading has been toward the smaller and smaller scales, it has continued to be a desire of model railroaders to assemble and operate a lifelike looking model railroad. With increasingly smaller scales of model railroad cars and railroad tracks, the desire for realistic looking model railroad cars has led to some difficulties in the operating of the model railroad layouts. For example, as the scale or size of model railroad cars decreases, the size of the couplers that releasably connect adjacent model railroad cars on a section of model railroad track must also decrease to maintain a realistic appearance of the model railroad cars. The reliable operation of the couplers of model railroad cars has always been a problem in the operation of model railroad layouts, and as the scales have gotten smaller these problems have become more pronounced.
The problems encountered with the reliable operation of smaller model railroad cars exist because, as the scale of the model railroad cars gets smaller and smaller, the need for the precise construction and assembly of the coupler component parts increases proportionately. Furthermore, this is true not only in the construction of model railroad cars and their couplers, but is also true in the construction of the model railroad track and in the quality of the laying of the track in a model railroad layout. For mechanical couplers or nonmagnetic couplers of model railroad cars to work well, each individual coupler of the pair to be connected must be properly aligned, both vertically and horizontally, with every other pair of couplers in use. It can easily be seen that as the scale of the model railroad cars gets smaller and smaller, this becomes more and more difficult. Irregularities in model railroad track, the dimensional tolerances of the wheels, trucks, and couplers of the model railroad cars, and the thermal stability of the model railroad track all get more critical as the scale decreases. In addition, as the scale of the model railroad cars gets smaller, the forces needed to operate the mechanical couplers pose a greater risk of causing a derailment of the cars.
In efforts to reduce the problems encountered with the operation of model railroad car couplers, manufacturers of the mechanical types of couplers that employ two or more moving parts have, in some cases, increased the size of the magnetic coupler relative to the scale of the model railroad car. However, this has the disadvantage of giving up the realism of the appearance of the railroad car and its couplers. In addition, some mechanical couplers have been designed that can only couple and uncouple along straight lengths of track or along only slightly curved lengths of track, sacrificing the realism of the functioning of the mechanical couplers.
Another factor demonstrating the need for model railroad car couplers that function with increased reliability is the increase in computer controlled model railroad layouts. Computer controlled model railroad layouts tend to be more unattended by the individual(s) operating the layout. Therefore, computer controlled layouts require a very high degree of reliability in all aspects of the functioning of the model railroad car couplers.
The difficulties encountered in the functioning of mechanical model railroad car couplers for the smaller scale model railroad cars have been addressed by the design of model railroad car couplers that use cooperating magnetic fields to form the releasable connection between adjacent model railroad cars. Model railroad car couplers that use cooperating magnetic fields have been found to be far more reliable in coupling and uncoupling operations, but have not achieved popularity primarily because they have tended to be large in size relative to the scale of the model railroad cars, and are often complex in construction.
Another disadvantage associated with model railroad car magnetic couplers is that many require that the two adjacent model railroad cars coupled by the magnetic couplers be grasped manually and pulled apart from each other in order to uncouple the magnetic couplers. Alternatively, a wedging tool is sometimes used by inserting the tool between the adjacent coupled cars and manually applying sufficient force to physically wedge the model railroad cars apart, uncoupling the magnetic couplers. These procedures can result in causing damage to the constructions of the model railroad cars being uncoupled, or in unwanted derailments of one or both of the cars. These procedures also require direct intervention by the model railroad operator at each pair of railroad cars being uncoupled. The procedures are inconvenient in manually operated model railroad layouts, and are undesirable for computer controlled model railroad layouts.
What is needed to overcome the disadvantages associated with the couplers of smaller scale model railroad cars is an improved coupling and uncoupling system that is self-aligning, and can operate reliably when manually unattended to couple or uncouple adjacent model railroad cars without causing damage to the cars or derailments of the cars.

Magnetic coupling and uncoupling system for model railroad rolling stock


A semiconductor device such as a diode or transistor includes a semiconductor substrate, a first region of III-V semiconductor material on the semiconductor substrate and a second region of III-V semiconductor material on the first region. The second region is spaced apart from the semiconductor substrate by the first region. The second region is of a different composition than the first region. The semiconductor device further includes a buried contact extending from the semiconductor substrate to the second region through the first region. The buried contact electrically connects the second region to the semiconductor substrate.

Conventional GaN high voltage Schottky diodes can be classified into two main categories: lateral devices and vertical devices. Lateral GaN Schottky diodes make use of a 2DEG (two dimensional electron gas) inherently provided by a conventional AlGaN/GaN system and require a minimum lateral distance between the anode and cathode contacts to sustain a high voltage. Vertical GaN Schottky diodes typically make use of a GaN buffer and do not require the presence of a lateral 2DEG channel. Instead, the anode is formed on the top a lightly doped GaN buffer and the cathode is represented by a lower contact disposed at the bottom of the GaN buffer. In order to have a good bottom contact, a highly doped layer is needed between the bottom contact and the GaN buffer.
The presence of a high mobility 2DEG in lateral diode devices achieves high current compared to their vertical counterparts. However vertical diode devices have better area efficiency due to the current flow direction and therefore have considerably reduced device dimensions as compared to lateral devices. Moreover, a Schottky contact directly placed on top of a GaN buffer results in a lower forward bias when compared with an AlGaN/GaN system. It therefore would be desirable to have a GaN device possessing the high current advantage of conventional lateral GaN devices and the area efficiency and low forward bias of conventional vertical GaN devices.

III-V semiconductor devices with buried contacts