Abstract: A new fiber optic based beamforming architecture for a time steered phased rray antenna based on chirped fiber gratings. All of the gratings are identical in length and period chirp so that they all have the same dispersion, thus at a given optical wavelength they have the same time delay. In a preferred embodiment an optical signal is modulated with an RF signal. The RF modulated optical is split and a portion propagates through a length of fiber to a photodetector feeding an antenna array. The second portion of the optical signal is routed through a circulator, which feeds the optical signal to a chirped fiber grating. The grating reflects and delays the optical signal back to the circulator which routes the reflected optical signal to a second coupler. The amount of delay incurred is determined by the grating dispersion and the wavelength of the optical source.

Abstract: Heterostructure field-effect transistors (HFETs) and other electronic devs are fabricated from a series of semiconductor layers to have reduced impact ionization. On to a first barrier layer there is added a unique second subchannel layer having high quality transport properties for reducing impact ionization. A third barrier layer having a controlled thickness to permit electrons to tunnel through the layer to the subchannel layer is added as a spacer for the fourth main channel layer. A fifth multilayer composite barrier layer is added which has at least a barrier layer in contact with the fourth channel layer and on top a sixth cap layer is applied. The device is completed by adding two ohmic contacts in a spaced apart relationship on the sixth cap layer with a Schottky gate between them which is formed in contact with the fifth barrier layer.

Abstract: A method for producing divalent scandium includes heating, at a mildly elted temperature above 20.degree. C. under reduced pressure, a calcium difluoride crystal sample doped with scandium trifluoride to drive off atmospheric impurities, heating at an intermediate temperature above 150.degree. C. calcium metal under reduced pressure to drive off volatile impurities, heating calcium metal at a migrating below 900.degree. C. to evaporate calcium and to deposit it on the sample, and heating the sample at a diffusion and reaction temperature below 950.degree. C. to diffuse calcium into the sample and to cause formation of the divalent scandium.

Abstract: In accordance with one aspect of the invention, a ring laser configuration having a polarizer, and whose cavity loop has substantially no net dispersion, permitting mode locked pulsing of high intensity and large bandwidth. In accordance with another aspect of the invention, a system using this laser to interrogate a plurality of arrays of Bragg gratings by use of both time and wavelength division multiplexing, increasing the total number of interrogatable gratings. In accordance with a third aspect of the invention, a system for interrogating one or more fiber Bragg gratings separated from the optical source by a dispersive optical fiber. As such a grating distends responsive to some measurand, its reflection frequency changes, and the traversal time of the reflection over the dispersive fiber changes, permitting inference of the measurand.

Abstract: An electron emitting device characterized by a monocrystalline substrate, a plurality of monocrystalline nanomesas or pillars disposed on the subste in a spaced relationship and extending generally normally therefrom, monocrystalline self-assembled tips disposed on top of the nanomesas, and essentially atomically sharp apexes on the tips for field emitting electrons. A method for making the emitters is characterized by forming a gate electrode and gate electrode apertures before forming the tips on the nanomesas.

Abstract: A channelized active bandpass filter having only two branches which provide respective frequency-selective feed-forward signal paths. The two signal aths have overlapping frequency response bands such that the combination of the two paths provides a composite filter with a bandpass response. The two branches may be provided with bandpass transfer characteristics of different orders and shapes, such as a second-order response and a fourth-order response. Two-way signal splitting and combining to define the two channels may be performed with in-phase splitters and combiners, for example, or diplexer circuits, each composed of two bandpass filters with different characteristics but overlapping frequency responses and preferably approximately equal center frequencies. Combinations of the two splitting and combining arrangements are also usable.

Abstract: Nanocrystalline semiconductors are synthesized within a bicontinuous cubic atrix 10. The nanocrystalline particles 12 may then be end-capped 18 with a dispersant to prevent agglomeration. One typical nanocrystalline semiconductor compound made according to the present invention is PbS. Other IV-VI semiconductors may be produced by the method of the present invention. The method of this invention may also be used to produce doped semiconductors.

Abstract: A Nuclear Quadrupole Resonance (NQR) method and apparatus for detecting the presence of a nitramine explosive, with a reduced probability of spurious triggering of consumer electronics. In the method and apparatus, a signal is emitted towards a nitramine explosive so that a nitro group in the namine explosive produces an NQR resonance signal. The NQR resonance signal is then detected to thereby detect the presence of the nitramine explosive. If the nitramine explosive is RDX, the NQR resonance signal of the nitro group is at a frequency which is either 502.3 kHz, 500.5 kHz, 405.1 kHz, 396.2 kHz or 384.1 kHz. Such frequencies are much lower than those in conventional detection techniques. As a result, the probability of the undesirable spurious triggering of electronic items exposed to the NQR RF pulses will be reduced, due to the reduction in induced voltage at lower frequency. The detection sensitivity is also reduced, but in many cases will still be adequate to detect nitramine explosives.

Abstract: An improved biological aerosol chemiluminescent (CL) detection system having optimal sensitivity and a method for using the same in detecting the presence of biological materials in an aerosol sample. The detection system comprises a cyclone aerosol sampler, a CL reagent injector, and a luminometer, wherein the CL reagent injector is mated with the cyclone aerosol sampler so as to deliver/introduce CL reagent thereto. The inner surface of the cyclone aerosol sampler and the inner surface of the CL reagent injector are fabricated from materials that are free of metals that would initiate a CL-based reaction with a CL reagent to be employed therein so as to provide a CL reagent path free of these metals. The entire CL reagent path in the biological aerosol CL detection apparatus is comprised of these materials. A method for determining the suitability of materials for use throughout the CL reagent path of the biological CL detection system is also taught.

Abstract: A secure communications system which comprises a laser-sending system and a light receiver. The laser light is divided into two beams, one beam is modulated to add the signal thereto, then the beams are recombined and directed to the receiver. The receiver then separates and demodulates the signal.

Abstract: The present invention is a method for determining a carrier conductivity-rier mobility spectrum for a semiconductor sample, having the steps of: exposing the semiconductor sample to a range K of discrete magnetic fields k=1,2, . . . K; for each field obtaining a Hall coefficient R.sub.H and a resistivity .rho., and calculating from R.sub.H (B.sub.k) and .sigma.(B.sub.k) experimental conductivity tensor components .sigma..sub.xx.sup.k (exp) and .sigma..sub.xy.sup.k (exp), and slopes of these conductivity tensor components .sigma.'.sub.xx.sup.k (exp) and .sigma.'.sub.xy.sup.k (exp); selecting a trial carrier conductivity-carrier mobility spectrum s.sub.i corresponding to a plurality I of carrier mobilities .mu..sub.i, i=1,2, . . . I; for each B.sub.j, using this trial carrier conductivity-carrier mobility spectrum to calculate conductivity tensor components .sigma..sub.xx.sup.j and .sigma..sub.xy.sup.j, and slopes of the conductivity tensor components .sigma.'.sub.xx.sup.j and .sigma.'.sub.xy.sup.

Abstract: A cone-tipped penetrometer for in situ analysis of soil or sediment by X-ray fluorescence spectroscopy. Rather than using a radioactive source, a miniature x-ray tube is powered by a filament isolation transformer located inside the penetrometer pipe which has an outside diameter of about 2 inches or less. The x-rays pass out through a special x-ray transmissive window, such as a low metal impurity-containing high strength boron carbide, into the soil or sediment below the surface and the resulting x-rays from the metals in the soil or sediment return through the window to a detector. The signal is transmitted back up to the surface where the x-rays are quantitatively analyzed to determine the concentration of metals in the soil. This real-time in situ x-ray fluorescence spectroscopy of soil or sediment samples permits field analysis of hazardous waste sites and other underground soil and underwater sediments.

Abstract: A robust, nontoxic, antifouling coating and bulk material and process for king the same are disclosed. The antifouling coating comprises a basecoat formed typically from a polyol and a poiyiisocyanate wherein a molar excess of poiyiisocyanate is typically used. A topcoat is formed on the basecoat by reacting the basecoat with aliphatic branched or unbranched mono-alcohol or polyol.

Abstract: Nanocrystalline phosphors are formed within a bicontinuous cubic phase. The phosphors are doped with an optimum concentration, of manganese, for example, corresponding to about one or less dopant ions per phosphor particle.

Abstract: The stripline-slotline digital phase shifter is located between a ground plane associated with a patch antenna and another ground plane associated with the other patch antenna, or other output circuits. It is comprised of a section of stripline adjacent to a slot in ground plane associated with the receiving patch antenna which transitions an input electromagnetic signal to a plurality of oval slotlines, called bit circuits, of varying lengths which form a delay circuit by shifting the phase of the input electromagnetic signal. The varying lengths of slotline are switched into and out of the circuit to provide a predetermined amount of delay and the phase adjusted electromagnetic signal is transitioned to portion of stripline adjacent to a slot associated with the transmission patch antenna or other output circuits.

Abstract: The fiber-optic pipette (FOP) couples a glass capillary, common syringe and a single optical fiber together to provide for a facile means of achieving long-pathlength capillary spectroscopy. The FOP acquires rapid spectroscopic measurements of small-volume liquid samples, while simultaneously achieving signal enhancements of the collected spectroscopic signal.

Abstract: An optically-stimulated luminescent radiation dosimeter system for the ree monitoring of radiation sources is disclosed. The system includes a radiation-sensitive optically-stimulated dosimeter which utilizes a new, doped glass material disposed at a remote location for storing energy from ionizing radiation when exposed thereto and for releasing the stored energy in the form of optically-stimulated luminescent light at a first wavelength when stimulated by exposure to light energy at a stimulating second wavelength.

Abstract: An article includes a diamond substrate which is securely adhered to a rot layer of silica layer that cannot be scratched by a tungsten probe or delaminated from the diamond substrate by pulling on a gold wire secured to the silica layer. This aricle can be made by electrochemically cleaning the diamond substrate to remove non-diamond carbon adhering thereto, depositing a fragile layer of silica layer which weakly bonds to the cleaned diamond, and annealing the fragile silica layer to convert it into a strongly bonded and robust silicon dioxide layer. The article is particularly useful in electronics, and has a low leakage current and low responsiveness to visible light.

Abstract: An ultrasonic energy source is used to provide a variable force for measuring the binding forces between molecular entities and for sensing the presence of an analyte in a test sample. The device includes a surface that has a first binding member attached thereto and one or more particles that have a second binding member attached thereto. A reaction vessel is provided for exposing the surface to the particles whereby, if the first binding member has a binding affinity for the second binding member, a complex is formed between individual first binding members and individual second binding members and the particles thereby become immobilized with respect to the surface. The ultrasonic energy source is positioned for applying a variable ultrasonic force onto the surface, and the position of the particles is monitored as the intensity of the ultrasonic force is varied.

Abstract: The present invention is a process for making complex structures with nanoscale resolution in parallel by placing an NCG replica-based mask (or other suitable mask) in close proximity to a substrate and controlling, with nanoscale accuracy and precision, the relative movement of the mask and substrate while sequentially or concurrently carrying out a patterning process or processes. Another aspect of the invention is a diamond film with submicron and/or nanoscale features, that can be made by the method of the invention.