摘要:
Water absorption resistant polyimide/epoxy-based compositions, like pastes (or solutions), are particularly useful to make electronic screen-printable materials and electronic components. A group of hydrophobic epoxies (and soluble polyimides) was discovered to be particularly resistant to moisture absorption. The polyimide/epoxy pastes made with these epoxies (and these polyimides) may optionally contain thermal crosslinking agents, adhesion promoting agents, blocked isocyanates, and other inorganic fillers. The polyimide/epoxy pastes of the present invention can have a glass transition temperature greater than 250° C., a water absorption factor of less than 2%, and a positive solubility measurement.
摘要:
Provided are compositions containing 20 to 50% by volume of a nitride or carbide of a group IV metal, a polymer, and 1 to 9% by volume of an allotrope of carbon. The compositions are useful in manufacturing resistors with low temperature coefficients of resistivity.
摘要:
Provided are compositions containing 20 to 50% by volume of a nitride or carbide of a group IV metal, a polymer, and 1 to 9% by volume of an allotrope of carbon. The compositions are useful in manufacturing resistors with low temperature coefficients of resistivity.
摘要:
A crystalline alpha-chromium oxide where from about 0.05 atom % to about 2 atom % of the chromium atoms in the alpha-chromium oxide lattice are substituted by nickel atoms, and optionally, additional chromium atoms in the alpha-chromium oxide lattice are substituted by trivalent cobalt atoms (provided that the total amount of the nickel atoms and the trivalent cobalt atoms in the alpha-chromium oxide lattice is no more than 6 atom %) is disclosed. Also disclosed is a chromium-containing catalyst composition comprising as a chromium-containing component the crystalline substituted alpha-chromium oxide; and a method for preparing a composition comprising the crystalline substituted alpha-chromium oxide. The method comprises (a) co-precipitating a solid by adding ammonium hydroxide to an aqueous solution of a soluble divalent nickel salt, a soluble trivalent chromium salt, and optionally, a soluble divalent or trivalent cobalt salt, that contains at least three moles of nitrate per mole of chromium in the solution, has a nickel concentration of from about 0.05 mole % to about 2 mole % of the total of nickel, chromium, and cobalt in the solution, and has a combined concentration of nickel and cobalt of no more than 6 mole % of the total of nickel, chromium, and cobalt in the solution; and after at least three moles of ammonium per mole of chromium has been added to the solution; (b) collecting the co-precipitated solid formed in (a); (c) drying the collected solid; and (d) calcining the dried solid. Also disclosed is a chromium-containing catalyst composition comprising a chromium-containing component prepared by treating said crystalline substituted alpha-chromium oxide with a fluorinating agent; and a process for changing the fluorine distribution (i.e., content and/or arrangement) in a hydrocarbon or halogenated hydrocarbon in the presence of a catalyst. The process involves using as the catalyst a composition comprising the crystalline substituted alpha-chromium oxide and/or the treated substituted alpha-chromium oxide.
摘要:
This invention provides the three novel La,Fe, La,Cr and Sm,Fe substituted barium titanate solid solution ferroelectric compositions with the formula Ba1-xLnxTi1-xMxO3 wherein when Ln is La, M is Fe or Cr, when Ln is Sm, M is Fe and x is from about 0.02 to about 0.06 and mixtures thereof, the novel La,Fe substituted barium strontium titanate solid solution ferroelectric compositions with the formula (Ba1-ySry)1-xLaxTi1-xFex O3 wherein y is greater than zero and less than about 0.6 and x is from about 0.01 to about 0.06 and the novel La,Al substituted barium strontium titanate solid solution ferroelectric compositions with the formula (Ba1-ySry)1-xLax Ti1-x/4 3a/4Ala(x-a)/4O3 wherein denotes a vacancy, y is greater than zero and less than about 0.6, a is from about 0.01 to about 0.06 and x is from 0.02 to about 0.10 with the proviso that x is greater than or equal to a. These low loss tunable ferroelectric compositions are especially useful in tunable microwave thin film devices which fall into three types: interdigital and trilayer capacitors, coplanar waveguides and microstrips.
摘要翻译:本发明提供了三种新的La,Fe,La,Cr和Sm,Fe取代的钛酸钡固溶体铁电组合物,其具有下式:Ba 1-x L x x Ti 其中当Ln为La时,M为Fe或Cr,当Ln为Sm时,M为Fe,x为 约0.02至约0.06及其混合物,新型La,Fe取代的钛酸钡锶钛酸盐固体铁电组合物,其具有式(Ba 1-y S y S y) 1-xLa x 1 Ti 1-x x Fe x O 3其中y大于 零和小于约0.6,x为约0.01至约0.06,并且新型La,Al取代的钛酸锶钡固溶体铁电组合物具有式(Ba 1-y S y y y) (xa)/ 4< 1< 1> 1< x 1 / 其中表示空位,y大于0且小于约0.6,a为约0.01至约0。 06和x为0.02至约0.10,条件是x大于或等于a。 这些低损耗可调铁电组合物在可调谐微波薄膜器件中特别有用,它们分为三种类型:交叉指型和三层电容器,共面波导和微带。
摘要:
A crystalline lead-containing oxyfluoride of the formula PbMO.sub.2 F wherein M is selected from the group consisting of Ga, Sc, In, Lu, Yb, Tm, Er and Tl.
摘要:
The present invention provides an indium-doped Co4Sb12 skutterudite composition in which some Co on the cubic lattice structure may be replaced with one or more members of the group consisting of Fe, Ni, Ru, Rh, Pd, Ir and Pt; some Sb on the planar rings may be replaced by one or more members of the group consisting of Si, Ga, Ge and Sn; and a second dopant atom is selected from a member of the group consisting of Ca, Sc, Zn, Sr, Y, Pd, Ag, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. The composition is useful as a thermoelectric material. In preferred embodiments, the composition has a figure of merit greater than 1.0. The present invention also provides a process for the production of the composition, and thermoelectric devices using the composition.
摘要:
This invention provides compositions of the formula EuCu3M4O12 wherein M is Ge, Ti, Sn or mixtures thereof. These compositions have high dielectric constant and low loss over a frequency range of from 1 kHz to 1 MHz.
摘要:
This invention provides novel thermoelectric compounds comprising: a) atomic percent Ytterbium b) between 50 and 74.999 atomic percent Aluminum c) between 0.001 and 25 atomic percent Manganese and a process for their preparation.
摘要:
Compositions having the nominal formula BiaSrbCacCu3Ox wherein a is from about 1 to 3, b is from about ⅜ to 4, c is from about {fraction (3/16)} to 2, x=(1.5 a+b+c+y) where y is from about 2 to 5, with the proviso that “b+c” is from about {fraction (3/2)} to 5, containing a metal oxide phase of the formula Bi2Sr3−zCazCu2O8+w wherein z is from about 0.1 to 0.9 w is greater than zero but less than 1, are superconducting. Processes for manufacturing such compositions and for using them are disclosed.
摘要翻译:具有标称式a的组合物为约1至3,b为约3/8至4,c为约{分数(3/16至2,x =(1.5a + b + c + y),其中 约2至5,条件是“b + c”为大约{级分(3/2至5,含有式Bi2Sr3-zCazCu2O8 + w的金属氧化物相,其中z为约0.1至0.9w大于 零但小于1,是超导的。公开了制造这种组合物和使用它们的方法。