Abstract: Some variations provide an additively manufactured metal-containing component comprising (i) nickel, (ii) aluminum and/or titanium, and (iii) nanoparticles, wherein the sum of aluminum weight percentage and one-half of titanium weight percentage is at least 3 on a nanoparticle-free basis, and wherein the additively manufactured metal-containing component has a microstructure that is substantially crack-free with equiaxed grains. A feedstock composition is also provided, comprising metal-containing microparticles and nanoparticles, wherein the nanoparticles are chemically and/or physically disposed on surfaces of the microparticles, wherein the microparticles comprise (i) nickel and (ii) aluminum and/or titanium, and wherein the sum of aluminum weight percentage and one-half of titanium weight percentage is at least 3 on a nanoparticle-free basis.

Abstract: Some variations provide a functionalized composite material comprising: a thermoplastic polymer binder matrix disposed in a distinct volume; a plurality of discrete metal or metal alloy particles dispersed in the thermoplastic polymer matrix; and a plurality of discrete particulates assembled on surfaces of the discrete metal or metal alloy particles, wherein the discrete particulates are in contact with the thermoplastic polymer binder matrix, wherein the discrete particulates are smaller than the discrete metal or metal alloy particles in at least one dimension, and wherein the discrete particulates are compositionally different than the discrete metal or metal alloy particles. The discrete particulates may be selected and/or configured to function as a grain refiner, a sintering aid, and/or a strengthening phase, within the functionalized composite material.

Abstract: Some variations provide a thermoformable and thermosettable bismaleimide-thiol-epoxy resin composition comprising: a thiol-endcapped bismaleimide monomer or oligomer; a thiol-containing species; an epoxy species; a curing catalyst; and optional additives. Other variations provide a method of making a bismaleimide-thiol-epoxy resin composition, comprising: providing a starting bismaleimide, a starting multifunctional amine, a starting multifunctional thiol, an acid catalyst, and a solvent to form a starting reaction mixture; reacting the bismaleimide, the multifunctional amine, and the multifunctional thiol to form a thiol-endcapped bismaleimide monomer or oligomer; providing a thiol-containing species; providing at least one epoxy species; providing a curing catalyst; and combining the thiol-endcapped bismaleimide monomer or oligomer, the thiol-containing species, the epoxy species, and the curing catalyst, to form a bismaleimide-thiol-epoxy resin composition.

Abstract: A transition metal dichalcogenide (TMD) transistor includes a substrate, an n-type two-dimensional (2D) TMD layer, a metal source electrode, a metal drain electrode, and a gate dielectric. The substrate has a top portion that is an insulating layer, and the n-type 2D TMD layer is on the insulating layer. The metal source electrode, the metal drain electrode, and the gate dielectric are on the n-type 2D TMD layer. The metal gate electrode is on top of the gate dielectric and is between the metal source electrode and the metal drain electrode.

Abstract: A HEMT comprising a channel layer of a first III-Nitride semiconductor material, grown on a N-polar surface of a back barrier layer of a second III-Nitride semiconductor material; the second III-Nitride semiconductor material having a larger band gap than the first III-Nitride semiconductor material, such that a positively charged polarization interface and two-dimensional electron gas is obtained in the channel layer; a passivation, capping layer, of said first III-Nitride semiconductor material, formed on top of and in contact with a first portion of a N-polar surface of said channel layer; a gate trench traversing the passivation, capping layer, and ending at said N-polar surface of said channel layer; and a gate conductor filling said gate trench.

Abstract: Some variations provide an atomic instrument configured with an optically transparent and electrochemically cleanable window, comprising: a transparent first electrode; a second electrode with an atom reservoir for first metal ions; an ion conductor interposed between the first electrode and a second electrode, wherein the ion conductor is capable of transporting second metal ions, wherein the ion conductor is in contact with the first electrode and with the second electrode, and wherein the ion conductor is optically transparent; and a transparent window support in contact with the ion conductor, wherein the electrochemically cleanable window is optically transparent, wherein the transparent window support, the ion conductor, and the first electrode collectively form a transparent and electrochemically cleanable window.

Abstract: Infrared-transparent polymers, useful for LWIR and/or MWIR transparency, are disclosed. The disclosed infrared-transparent polymers are low-cost, damage-resistant, and economically scalable to commercially relevant substrate areas (1 ft2 and greater). In some disclosed infrared-transparent polymers, the carbon-free polymer backbone contains a plurality of polymer repeat units of the form wherein R1 is selected from the group consisting of alkyls, hydroxyl, amino, urea, thiol, thioether, amino alkyls, carboxylates, metals, metal-containing groups, and deuterated forms or combinations thereof; wherein R2 is (independently from R1) selected from the group consisting of alkyls, hydroxyl, amino, urea, thiol, thioether, amino alkyls, carboxylates, metals, metal-containing groups, and deuterated forms or combinations thereof; wherein n is selected from 2 to about 10,000; and wherein the carbon-free polymer backbone is linear, cyclic, branched, or a combination thereof.

Abstract: In some variations, an interferometric frequency-reference apparatus comprises: an atom source configured to supply neutral atoms; a collimator configured to form a collimated beam of the neutral atoms; one or more probe lasers; and a Doppler laser configured to determine a ground-state population of the neutral atoms. Other variations provide a method of creating a stable frequency reference, comprising: forming a collimated beam of neutral atoms; illuminating the neutral atoms with first and second probe lasers; adjusting the frequencies of the first probe laser and second probe laser using Ramsey spectroscopy to an S?D transition of the neutral atoms; and determining a ground-state population of the neutral atoms with another laser. The interferometric frequency-reference apparatus may provide an optical frequency reference or a microwave frequency reference.

Abstract: Some variations provide a process for additive manufacturing of a nanofunctionalized metal alloy, comprising: providing a nanofunctionalized metal precursor containing metals and grain-refining nanoparticles; exposing a first amount of the nanofunctionalized metal precursor to an energy source for melting the precursor, thereby generating a first melt layer; solidifying the first melt layer, thereby generating a first solid layer; and repeating many times to generate a plurality of solid layers in an additive-manufacturing build direction. The additively manufactured, nanofunctionalized metal alloy has a microstructure with equiaxed grains.

Abstract: This disclosure provides corrosion-resistant coatings that significantly improve corrosion resistance compared to the prior art. The corrosion protection system senses gradients in electrical potential, pH, and metal ion concentration, and then automatically halts corrosion. Some variations provide a gradient-responsive corrosion-resistant coating comprising: a first layer comprising a transition metal oxide and mobile cations; a second layer comprising a biphasic polymer, wherein the biphasic polymer contains ionic groups, wherein the biphasic polymer comprises a discrete phase and a continuous transport phase, wherein the continuous transport phase is capable of delivering oligomers in response to corrosion byproducts, and wherein the oligomers are ionically crosslinkable with metal cations from a base metal substrate.

Abstract: This disclosure provides resin formulations which may be used for 3D printing and thermally treating to produce a ceramic material. The disclosure provides direct, free-form 3D printing of a preceramic polymer, followed by converting the preceramic polymer to a 3D-printed ceramic composite with potentially complex 3D shapes. A wide variety of chemical compositions is disclosed, and several experimental examples are included to demonstrate reduction to practice. For example, preceramic resin formulations may contain a carbosilane in which there is at least one functional group selected from vinyl, allyl, ethynyl, unsubstituted or substituted alkyl, ester group, amine, hydroxyl, vinyl ether, vinyl ester, glycidyl, glycidyl ether, vinyl glycidyl ether, vinyl amide, vinyl triazine, vinyl isocyanurate, acrylate, methacrylate, alkacrylate, alkyl alkacrylate, phenyl, halide, thiol, cyano, cyanate, or thiocyanate.

Abstract: A method and an apparatus for coupling two nonlinear resonators via a nonlinear element to generate phononic frequency combs.

Abstract: Some variations provide a method of forming a transparent icephobic coating, comprising: obtaining a hardenable precursor comprising a first component and a plurality of inclusions containing a second component, wherein one of the first component or the second component is a low-surface-energy polymer, and the other is a hygroscopic material; applying mechanical shear and/or sonication to the hardenable precursor; disposing the hardenable precursor onto a substrate; and curing the hardenable precursor to form a transparent icephobic coating. The coating contains a hardened continuous matrix containing regions of the first component separated from regions of the second component on an average length scale of phase inhomogeneity from 10 nanometers to 10 microns, such as less than 1 micron, or less than 100 nanometers. The transparent icephobic coating may be characterized by a light transmittance of at least 50% at wavelengths from 400 nm to 800 nm, through a 100-micron coating.

Abstract: In some variations, an interferometric frequency-reference apparatus comprises: an atom source configured to supply neutral atoms to be ionized; an ionizer configured to excite the neutral atoms to form ionized atoms; an ion collimator configured to form a collimated beam of the ionized atoms; probe lasers; and a Doppler laser configured to determine a ground-state population of the ionized atoms, wherein the atom source, the ionizer, and the ion collimator are disposed within a vacuum chamber. Other variations provide a method of creating a stable frequency reference, comprising: forming ionized atoms from an atomic vapor; forming a collimated beam of ionized atoms; illuminating ionized atoms with first and second probe lasers; adjusting the frequencies of the first probe and second probe lasers using Ramsey spectroscopy to an S?D transition of ionized atoms; and determining a ground-state population of the ionized atoms with another laser.

Abstract: Some variations provide a method of making an additively manufactured single-crystal metallic component, comprising: providing a feedstock comprising a first metal or metal alloy; providing a build plate comprising a single crystal of a second metal or metal alloy; exposing the feedstock to an energy source for melting the feedstock, generating a melt layer on the build plate; and solidifying the melt layer, generating a solid layer (on the build plate) of a metal component. The solid layer is also a single crystal of the first metal or metal alloy. The method may be repeated many times to build the part. Some variations provide a single-crystal metallic component comprising a plurality of solid layers in an additive-manufacturing build direction, wherein the plurality of solid layers forms a single crystal of a metal or metal alloy with a continuous crystallographic texture. The crystal orientation may vary along the additive-manufacturing build direction.

Abstract: Disclosed herein is a shelf-stable, two-part formula for making an antimicrobial biphasic polymer. Some variations provide a two-part formula for fabricating a biphasic polymer, wherein the two-part formula consists essentially of (A) a first liquid volume, wherein the first liquid volume comprises: a structural phase containing a solid structural polymer; a transport phase containing a solid transport polymer; a chain extender; a curing catalyst; a first solvent; and (B) a second liquid volume that is volumetrically isolated from the first liquid volume, wherein the second liquid volume comprises: a crosslinker that is capable of crosslinking the solid structural polymer with the solid transport polymer; and a second solvent. An antimicrobial agent (e.g., quaternary ammoniums salts) may be contained in the first liquid volume or in the second liquid volume. Methods of making and using the antimicrobial biphasic polymer are described.

Abstract: Some variations provide a permanent-magnet structure comprising: a region having a plurality of magnetic domains and a region-average magnetic axis, wherein each of the magnetic domains has a domain magnetic axis that is substantially aligned with the region-average magnetic axis, and wherein the plurality of magnetic domains is characterized by an average magnetic domain size. Within the region, there is a plurality of metal-containing grains characterized by an average grain size, and each of the magnetic domains has a domain easy axis that is dictated by a crystallographic texture of the metal-containing grains. The region has a region-average easy axis based on the average value of the domain easy axis within that region. The region-average magnetic axis and the region-average easy axis form a region-average alignment angle that has a standard deviation less than 30° within the plurality of magnetic domains. Many permanent-magnet structures are disclosed herein.

Abstract: Some variations provide an atom vapor-density control system, the system comprising: a first electrode; a second electrode that is electrically isolated from the first electrode; an ion-conducting layer interposed between the first electrode and the second electrode, wherein the ion-conducting layer is in ionic communication with the second electrode; at least one atom reservoir in contact with the second electrode or with an additional electrode, wherein the atom reservoir is electrochemically configured to controllably supply or receive atoms; a heater in thermal communication with a heated region comprising the first electrode; and one or more thermal isolation structures configured to minimize heat loss out of the heated region into a cold region. Several exemplary system configurations are presented in the drawings. The disclosed atom vapor-density control systems are capable of controlling the vapor pressure of metal atoms (such as alkali atoms) at low electrical power input.

Abstract: Some variations provide an interspersed assembly of nanoparticles, the assembly comprising a first phase containing first nanoparticles and a second phase containing second nanoparticles, wherein the second phase is interspersed with the first phase, and wherein the first nanoparticles are compositionally different than the second nanoparticles. The interspersed assembly may be a semi-ordered assembly comprising discrete first-phase particles surrounded by a continuous second phase. Other variations provide a core-shell assembly of nanoparticles, the assembly comprising a first phase containing first nanoparticles and a second phase containing compositionally distinct second nanoparticles, wherein the second phase forms a shell surrounding a core of the first phase. The disclosed assemblies may have a volume from 1 ?m3 to 1 mm3, a packing fraction from 20% to 100%, and an average relative surface roughness less than 5%, for example.

Abstract: Some variations provide a leading-edge heat pipe comprising: (a) an envelope fabricated from a shell material, wherein the envelope includes at least one edge with a radius of curvature of less than 3 mm, and wherein the envelope includes, or is in thermal communication with, at least one heat-rejection surface; (b) a porous wick fabricated from a ceramic or metallic wick material, wherein the porous wick is configured within a first portion of the interior cavity, wherein at least a portion of the porous wick is adjacent to the inner surface, and wherein the porous wick has a bimodal pore distribution comprising an average capillary-pore size from 0.2 microns to 200 microns and an average high-flow pore size from 100 microns to 2 millimeters (the average high-flow pore size is greater than the average capillary-pore size); and (c) a phase-change heat-transfer material contained within the porous wick.