2,492 research outputs found
Use of the method of particular solutions in nonlinear, two-point boundary-value problems. Part 1 - Uncontrolled systems
Nonlinear two-point boundary-value problem solution by combined techniques of quasilinearization and method of particular solution
Use of the method of particular solutions in nonlinear, two-point boundary-value problems. Part 2 - Controlled systems
Method of particular solutions used to solve two point boundary value problem for nonlinear controlled syste
Development of an optical waveguide interferometric immunosensor
A Mach-Zehnder interferometer is presented, which uses the evanescent field of a planar optical waveguide as the sensing element. Changes in the refractive index profile occurring in the immediate vicinity of the waveguide surface cause the propagation velocity of the light passing through it to change. This is measured interferometrically. Adsorption processes of antibodies onto the waveguide surface as well as immunoreactions have been monitored. Concentrations of 2.5 Ă— 10Âż8 M (1 Ă— 10-3 mg/ml) of the antigen HCG (molecular weight = 39 600) have been measured so far
Performance of a highly sensitive optical waveguide Mach-Zehnder interferometer immunosensor
We describe a highly sensitive sensor which uses the evanescent field of a reusable planar optical waveguide as the sensing element. The waveguide used is optimized to obtain a steep dependence of the propagation velocity on the refractive-index profile near the surface. The adsorption of a layer of proteins thus results in a phase change, which is measured interferometrically using a Mach-Zehnder interferometer set-up. The stability of the interferometer is such that phase changes = (1 Ă— 10-2)2pi per hour can be measured. Immunoreactions have been monitored down to concentrations of 5 Ă— 10-11 M of a 40 kDa protein
Mathematical programming for constrained minimal problems. Part 1 - Sequential gradient, restoration algorithm
Algorithm using gradient and restoration phases for constrained minimal problem
An Analytical Study of Children\u27s Radio Listening Interest, Habits and Attitudes
June 30, 1946 was unique from an educator\u27s point of view. The radio, the press, and every conceivable means of communication had been pressed in to service to prepare the American public and the world at large for one of the greatest scientific experiments ever undertaken by man. In this group were, without doubt, many boys and girls of elementary school age, with interest heightened and curiosity sharpened by weeks of anxious waiting. Though the reception was generally poor due to static conditions and many older members of the group lost interest, these children were not satisfied till the announcer declared the job finished
Integrated optical directional coupler biosensor
We present measurements on biomolecular binding reactions, using a new type of integrated optical biosensor based on a planar directional coupler structure. The device is fabricated by Ag+-Na+ ion-exchange in glass and definition of the sensing region is achieved by use of transparent fluoropolymer isolation layers formed by thermal evaporation. The suitability of the sensor for application to the detection of environmental pollutants is considered
Conformal phased array with beam forming for airborne satellite communication
For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In this paper two key aspects of conformal phased array antenna arrays are addressed: the development of a broadband Ku-band antenna and the beam synthesis for conformal array antennas. The antenna elements of the conformal array are stacked patch antennas with dual linear polarization which have sufficient bandwidth. For beam forming synthesis a method based on a truncated Singular Value Decomposition is proposed
Phased array receive antenna steering system using a ring resonator-based optical beam forming network and filter-based optical SSB-SC modulation
A novel phased array receive antenna steering system is introduced. The core of this system is an optical ring resonator-based broadband, continuously tunable optical beam forming network (OBFN). In the proposed system architecture, filter-based optical single-sideband suppressed-carrier modulation and balanced coherent optical detection are used. \ud
Such architecture has significant advantages over a straightforward architecture using optical double-sideband modulation and direct optical detection, namely relaxed bandwidth requirements on the optical modulators and detectors, reduced complexity of the OBFN chip, and enhanced dynamic range. Initial measurements on an actual 1Ă—8 OBFN chip and an optical sideband filter chip are presented. Both are realized in CMOS-compatible planar optical waveguide technology.\u
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