1-24. (canceled)
25. A process for producing carbon aerogels impregnated with dispersed metal particles comprising:
contacting a diamine monomer and an aromatic dianhydride monomer in a solvent under conditions conducive to formation of a poly(amic acid);
dissolving a soluble metal ion salt and the poly(amic acid) in a solvent;
contacting the solution of poly(amic acid) and soluble metal ion salt with a dehydrating agent to form a polyimide gel by imidization of the poly(amic acid);
drying the polyimide gel in the presence of supercritical CO2 to afford an polyimide aerogel; and
pyrolyzing the derived aerogel under protection of an inert atmosphere to form the carbon aerogel having highly dispersed transition metal particles.
26. A process for producing carbon xerogel-aerogel hybrid impregnated with highly dispersed metal particles, the process comprising the steps of:
contacting a diamine monomer and an aromatic dianhydride monomer in a solvent under conditions conducive to formation of a poly(amic acid);
dissolving a soluble metal salt and the poly(amic acid) in a solvent;
contacting the solution of poly(amic acid) and soluble metal ion salt with a dehydrating agent to form a polyimide gel by imidization of the poly(amic acid);
precipitating at least a portion of the soluble metal salt onto the polyimide gel;
drying the polyimide gel in the presence of supercritical CO2 to afford an polyimide aerogel; and
pyrolyzing the derived aerogel under protection of an inert atmosphere to form the carbon xerogel-aerogel having highly dispersed transition metal particles.
27. A process for producing a metal carbide aerogel, a metal carbide-carbon aerogel or carbon aerogel impregnated with highly dispersed metal particles, the process comprising the steps of:
contacting a diamine monomer and an aromatic dianhydride monomer in a solvent under conditions conducive to formation of a poly(amic acid);
preparing a solution of a soluble metal ion salt, an epoxide compound and the poly(amic acid) in a solvent such that a molar ratio of epoxide compound to the metal ion is between about 1 to about 8;
contacting the solution of poly(amic acid), an epoxide compound and soluble metal ion salt with a dehydrating agent to form a polyimide gel by imidization of the poly(amic acid);
drying the polyimide gel in the presence of supercritical CO2 to afford an polyimide aerogel; and
pyrolyzing the derived aerogel under protection of an inert atmosphere to form the aerogel having highly dispersed transition metal particles.
28. The process of any one of claims 25 through 27 in which the first solvent is not miscible with supercritical CO2, the method further comprises the step of exchanging the first solvent with a second solvent which is miscible with supercritical CO2 prior to drying the polyimide gel.
29. The process of any one of claims 25 through 27, wherein the metal is selected from the group consisting of Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu, Ag, Zn, Si, Sn, Pb, Sb, Nb, Bi, Hf, Ba, Al, B, P, As and combinations thereof.
30. The process of claim 27, wherein the epoxide is a 1,2-epoxyalkane having from 2 to about 12 carbon atoms.
31. The process of claim 27, wherein the epoxide is selected from the group of 1,2-epoxybutane and 1,2-epoxypropane
32. The process of claim 27, wherein the epoxide compound is added to the reaction as an admixture with deionized water and wherein the epoxide compound is added to the reaction after gelation of the polyimide.
33. The process of claim 27, wherein the ratio of epoxide to metal ion is at range of about 1 to about 8.
34. The process of claim 27, wherein the ratio of deionized water to epoxide is about 1 to about 4.
35. The process of claim 28, wherein the process further comprises addition of a gelation controlling agent to the poly(amic acid) solution such that a molar ratio of gelation controlling agent to metal ion is between about 1 and about 8.
36. The process of claim 35, wherein the molar ratio of gelation controlling agent to metal ion is between about 1 and about 4.
37. The process of claim 35, wherein the gelation controlling agent is an optionally substituted acetoacetonate or an optionally substituted alkyl acetoacetate.
38. The process of claim 35, wherein the gelation controlling agent is selected from the group of 2,4-pentanedione and ethyl acetoacetate.
39. The process of any one of claims 25-27, wherein a reinforcing agent is added to the polyimide wet gel before drying with supercritical CO2.
40. The process of claim 39, wherein the reinforcing agent is selected from a reinforcement pad, organic or inorganic fibers carbon nanotubes, metallic fillers or particles or inorganic fillers or particles.
41. The process of claim 39, wherein the fiber reinforcement pad is selected from a non-woven or woven fiber reinforcement composed of a polymeric organic fiber, a glass fiber, a ceramic fiber, a carbon precursor fiber, or a biopolymer fiber.
42. The process of any one of claims 25-27, in which the process further comprises a post-curing step, at an elevated temperature, to induce substantially complete imidization, wherein the post curing step is conducted:
(a) prior to the solvent removal step wherein the post-curing step is conducted under a pressure of about 20 psi to about 4000 psi; or
(b) after the solvent removal step, wherein the post-curing step is conducted under an inert atmosphere or in a vacuum at a temperature of between about 50\xb0 C. to about 450\xb0 C.
43. The process of any one of claims 25-27, wherein the diamine monomer is represented by the formula H2N\u2014X\u2014NH2, wherein X represents a difunctional aliphatic hydrocarbon group, an amino-terminated polysiloxane, a difunctional aromatic hydrocarbon group, or difunctional heteroaromatic group which may be optionally substituted.
44. The process of claim 43, wherein the aromatic diamine is represented by either formula (I) and (II)
wherein X and Y are monofunctional substituents selected from hydrogen, halogen, carboxyl, lower alkyl and lower alkoxyl groups, X and Y may be the same or different substituents and A is a bivalent connecting group selected from \u2014O\u2014, \u2014S\u2014, \u2014CO\u2014, \u2014S\u2014, \u2014SO2\u2014, and \u2014CH2\u2014, or A is a single bond; wherein alkyl or alkoxy contains 1 to 4 carbon atoms.
45. The process of claim 44, wherein the aromatic diamine is 1,4-phenylenediamine or 4,4\u2032-diamino-biphenyl.
46. The process of claim 43, wherein the diamine monomer is an aliphatic diamine containing a linear alkyl chain unit of formula.
NH2\ue00cCH2\ue00dnNH2
wherein n is a integer number from 1 to 12.
47. The process of claim 43, wherein the diamine monomer is an amino terminated polysiloxane of the formula
wherein R1 and R2 are each independently selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted cycloalkyl, optionally substituted cycloalkyl-alkyl, optionally substituted aryl, optionally substituted aralkyl, and optionally substituted alkoxy.
48. The process of claim 47, wherein the amino terminated polysiloxane is a thermally stable polysiloxane of the formula
wherein R1 and R2 are independently selected from optionally substituted alkyl having from 1 to about 12 carbon atoms and optionally substituted phenyl.
49. The process of any one of claims 25-26, wherein the aromatic dianhydride is monomer represented by either formula III or IV
wherein X and Y are monofunctional substituents selected from hydrogen, halogen, carboxyl, alkyl, and alkoxy groups, X and Y may be the same or different substituents and A is a bivalent connecting group selected from \u2014O\u2014, \u2014S\u2014, \u2014CO\u2014, \u2014S\u2014, \u2014SO2\u2014, \u2014CH2\u2014, or A is a single bond.
50. The process of claim 49, wherein the aromatic dianhydride is selected from the group consisting of optionally substituted pyromellitic dianhydride, optionally substituted 3,3\u2032,4,4\u2032-biphenyltetracarboxylic dianhydride, optionally substituted 3,3\u2032,4,4\u2032-benzophenone tetracarboxylic dianhydride, and optionally substituted 2,3,6,7-naphthylene tetracarboxylic acid dianhydride.
51. The process of any one of claims 25-27, wherein the dehydrating agent comprises at least one compound selected from the group consisting of acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride, and phosphous trichloride.
52. The process of claim 43, wherein the organic base is selected from optionally substituted mono-, di- and trialkylamines, optionally substituted pyridines, optionally substituted isoquinoline, optionally substituted morpholine, optionally substituted piperadine, and optionally substituted piperazine.
53-79. (canceled)
80. A composite carbon aerogel comprising carbon and at least one metal where the composite aerogel is prepared by the process of any one of claims 25 through 27.
81. A composite metal-carbon aerogel comprising nitrogen doped carbon aerogel domains, metal carbide domains, or a combination thereof.
82. The composite metal-carbon aerogel of claim 81, wherein the composite aerogel comprises interpenetrating networks of a carbon aerogel and a metal carbide aerogel.
83. The composite metal-carbon aerogel of claim 81, wherein the composite aerogel further comprises 0.1 to about 15% nitrogen.
84. A composite metal-carbon aerogel of claim 81, having a yield strength of at least 1 MPa.
85. A composite metal-carbon aerogel of claim 81, wherein the aerogel has an average pore size of between about 5 nm and about 50 nm.
86. A composite metal-carbon aerogel of claim 81, wherein the aerogel has a surface area of about 100 m2g to about 1000 m2g.
87. A composite metal-carbon aerogel of claim 81, wherein the aerogel has a surface area of about 200 m2g to about 600 m2g.
88. The composite metal-carbon aerogel of claim 81, wherein the aerogel has nanoparticles of a second metal dispersed throughout pores of the aerogel where the second metal may be the same or different from the metal of the metal carbide component of the composite aerogel.
89. A composite metal-carbon aerogel of claim 88, wherein the second metal is selected from Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu, Ag, Zn, Si, Sn, Pb, Sb, Nb, Bi, Hf, Ba, Al, B, P, As and combinations thereof.
90. A composite metal-carbon aerogel of claim 80, in which the composite aerogel is electrically conductive.
91. A composite metal-carbon aerogel of claim 81, in which the composite aerogel is electrically conductive.
92. A composite metal-carbon aerogel of claim 82, in which the composite aerogel is electrically conductive.
93. A composite metal-carbon aerogel of claim 88, in which the composite aerogel is electrically conductive.
94. A metal carbide aerogel prepared by the process of claim 27.
95. The metal carbide aerogel of claim 94, wherein the composite aerogel further comprises 0.1 to about 15% nitrogen.
96. The metal carbide aerogel of claim 94 in which the metal carbide aerogel is electrically conductive.
97. A metal carbide aerogel of claim 94 having a yield strength of at least 1 MPa.
98. A metal carbide aerogel of claim 94, wherein the aerogel has an average pore size of between about 5 nm and about 50 nm.
99. A metal carbide aerogel of claim 94, wherein the aerogel has a surface area of about 200 m2g or more.
100. A metal carbide aerogel of claim 99, wherein the aerogel has a surface area of between about 200 m2g and about 1000 m2g.
101. The metal carbide aerogel of claim 94, wherein the aerogel has nanoparticles of a second metal dispersed throughout pores of the aerogel where the second metal may be the same or dfferent from the metal of the metal carbide component of the composite aerogel.
102. A composite metal-carbon aerogel of claim 101, wherein the second metal is selected from Ti, Zr, V, Nb, Cr, Mo, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Cu, Ag, Zn, Si, Sn, Pb, Sb, Nb, Bi, Hf, Ba, Al, B, P, As and combinations thereof.
103. A xerogelaerogel hybrid prepared by the process of claim 26.
104. An article of manufacture comprising at least one aerogel selected from metal carbide aerogels, hybrid carbon-metal carbide aerogels, each of which may have metal particles dispersed in the pores of the aerogel.
105. The article of manufacture of claim 104, wherein the aerogel is selected from aerogels provided by any one of claims 88, 81, 94 or 101.
106. An electrode composed of at least one aerogel selected from metal carbide aerogels, hybrid carbon-metal carbide aerogels, each of which may have metal particles dispersed in the pores of the aerogel.
107. The electrode of claim 106, wherein the aerogel is selected from aerogels provided by any one of claims 88, 81, 94 or 101.
108. An electrochemical cell comprising one or more electrodes composed of at least one aerogel selected from metal carbide aerogels, hybrid carbon-metal carbide aerogels, each of which may have metal particles dispersed in the pores of the aerogel.
109. The electrochemical cell of claim 108, wherein the aerogel is selected from aerogels provided by any one of claims 88, 81, 94 or 101.
110. An electrochemical cell of claim 108, wherein the electrochemical cell is selected from a battery, a capacitor, a supercapacitor, fuel cell, or capacitive deionization cell.
111. A supported metal catalyst comprising a metal carbide, or a composite carbon-metal carbide aerogel having metal particles dispersed therein or a metal carbide aerogel.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A night vision device comprising:
a housing, wherein the housing houses an intensifier tube;
a proximity sensor mounted on the housing;
an ONOFF switch operatively coupled to the intensifier tube and to the proximity sensor, wherein operation of the ONOFF switch to the \u201cON\u201d position automatically activates the proximity sensor; and
the proximity sensor comprises an infrared emitter electrically coupled to the ONOFF switch and an infrared detector disposed to receive a signal emitted from the infrared emitter and reflected from a body;
wherein the housing is mounted on a fixture and the housing is pivotably movable on the fixture between a first position, wherein the proximity sensor is within an activation distance of the body, and a second position, wherein the proximity sensor is not within activation distance of the body, and
the infrared detector is pivoted to the first position for receiving the signal emitted from the infrared emitter and reflected from the body, and the infrared detector is pivoted to the second position for not receiving a reflection from the body.
2. The night vision device according to claim 1, wherein the infrared emitter operates at a wavelength of at least 900 nanometers.
3. The night vision device according to claim 1, wherein the fixture comprises a helmet.
4. The night vision device according to claim 1, wherein the fixture comprises a rifle.
5. A method of operating a night vision device comprising a housing, wherein the housing houses an intensifier tube; a proximity sensor mounted on the housing; and an ONOFF switch operatively coupled to the intensifier tube and to the proximity sensor, wherein the method comprises the steps of:
pivotally mounting the night vision device on a support;
turning the ONOFF switch to the ON position;
pivoting the proximity sensor to a close proximity of a body to activate the intensifier tube; and
pivoting the proximity sensor from a close proximity of the body to deactivate the intensifier tube.
6. A night vision device comprising:
a support structure;
a night vision device mounted on the support structure and pivotably movable relative to the support structure between a first position and a second position, wherein the night vision device comprises:
a housing, wherein the housing houses an intensifier tube;
a proximity sensor mounted on the housing, wherein the proximity sensor is operatively coupled to the intensifier tube and includes an infrared emitter and detector; and
an ONOFF switch operatively coupled to the intensifier tube and to the proximity sensor, wherein operation of the ONOFF switch to the \u201cON\u201d position automatically activates both the intensifier tube and the proximity sensor;
wherein the infrared detector is pivoted to the first position for receiving a signal emitted from the infrared emitter and reflected from a body, and the infrared detector is pivoted to the second position for not receiving a reflection from the body.
7. The night vision device according to claim 6, wherein, when the night vision device is in the first position and the ONOFF switch is in the ON position, the proximity sensor activates the intensifier tube.
8. The night vision device according to claim 7, wherein, when the night vision device is in the second position and the ONOFF switch is in the ON position, the proximity sensor deactivates the intensifier tube.
9. A night vision assembly comprising:
a support structure; and
a night vision device mounted on the support structure, wherein the night vision device comprises:
a housing, wherein the housing houses an intensifier tube;
a proximity sensor mounted on the housing, wherein the proximity sensor is operatively coupled to the intensifier tube; and
an ONOFF switch operatively coupled to the intensifier tubes and to the proximity sensor, wherein operation of the ONOFF switch to the \u201cON\u201d position automatically activates the proximity sensor;
wherein, when the proximity sensor mounted on the support structure is proximate to an activating body, the proximity sensor activates the intensifier tube, and
when the proximity sensor mounted on the support structure is distal from the activating body, the proximity sensor deactivates the intensifier tube.