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Instruments that measure the scattering parameters of microwave circuits generally have large systematic errors due to unavoidable parasitics in the instruments. These errors can be modeled analytically, however, and removed through a calibration procedure. A personal computer is well suited to the performance of the required calculations. Combining a personal computer with a microwave network analyzer results in a flexible and accurate automatic instrument. Two such automatic network analyzers are presented here. A new type of network analyzer, known as a sampled-line network analyzer is presented. It is an extension of the six-port network analyzer concept developed at the National Bureau of Standards. It is a particularly simple implementation and shows promise for the construction of relatively low-cost microwave network analyzers....
A method is presented for estimating the effects of various parameters on the performance of a winged rocket. A program for studying three specific parameters, i.e., wing areas, reduced thrust cruising programs, and trajectory climb angles, and their effect on the horizontal range of a winged rocket is presented. Complete calculations are carried out for one combination of these parameters.
An analysis of the Lift, Drag and Stability characteristics of a long, slender rocket with trapezoidal fins and wings is made. The stabilizing effectiveness of delta and trapezoidal fins is compared.
Simplified approximate methods of integrating the trajectory equations by step-by-step method are presented.
Using both analytical approaches and finite difference time domain simulations, we investigate different types of waveguiding and coupling mechanisms, including direct coupling between the optical resonators, waveguide-resonator coupling, indirect resonator coupling via waveguide modes, and Bragg reflection in cylindrically symmetric geometries.
By coupling an array of high Q optical resonators together, we form a new type of waveguide, coupled resonator optical waveguide (CROW), where photons propagate by "hopping" from one resonator to its nearest neighbors. Using tight-binding approximation, we find that the CROW band dispersion can be simply characterized by a coupling coefficient [kappa]. The tight-binding results are confirmed by using the finite difference time domain algorithms to analyze two examples of CROW’s: one is com...
Numerical iterative methods of solution of the one-dimensional basic two-carrier transport equations describing the behavior of semiconductor junctions under both steady-state and transient conditions are presented. The methods are of a very general character: none of the conventional assumptions and restrictions are introduced, and freedom is available in the choice of the doping profile, generation-recombination law, mobility dependencies, injection level., and boundary conditions applied solely at the external contacts. For a specified arbitrary input signal of either current or voltage (as a function of time) the solution yields terminal properties and all the quantities of interest in the interior of the device, such as carrier densities, electric field, electrostatic potential, particle and displacement currents, as functions of ...
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This investigation demonstrates that new metal-chelating lipids formed into mixed vesicles can bind to a variety histidine-rich ligands through metal coordination. Our results show the feasibility of metal-chelating lipids as a method for targeting histidine-rich compounds to lipid interfaces. Interesting metal chelating lipid materials for protein orientation studies, matching the surface distribution of surface residues, protein drug delivery, and for two-dimensional protein crystallization could be made with chelating-lipids. Engineered proteins containing a histidine "tag" or proteins with natural surface histidine residues are easily targeted to the interface using metal binding.
Both metal binding and histidine-ric...
NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.
Let [...] be a measure space, and T a positive contraction of [...]. Let [...] be a sequence of non-negative numbers whose sum is one, and [...] a sequence defined by inductions as follows [...]. Now let [...], then we prove in this work that [...] exists almost everywhere in the set [...]. When [...] we get that all [...]. In this case (*) yields the abelian analog of the well-known ergodic theorem of Chacon-Ornstein dealing with the convergence of averages of the form [...] whose proof we have generalized and adapted to show the convergence of [...]. We have also considered the generalization of (**) to weighted averages [...] whose convergence in [...] was recently proved by G. E. Baxter. We have given a consid...
An integrated approach is presented for the on-line estimation of the state of a biochemical reactor from presently attainable real-time measurements. Elemental and macroscopic balances are used for the determination of the total rate of growth and state-of-the-art estimation techniques are subsequently employed for the elimination of process and measurement noise and the estimation of the state variables and unknown culture parameters. The proposed approach is very flexible in that as new sensors become available they can be easily incorporated within the present framework to estimate new variables or improve the accuracy of the old ones. The method does not require any model for the growth kinetics and is very sucessful in accurately estimating the above variables in the presence of intense noise and under both steady state and trans...
Unnatural amino acid (UAA) incorporation is an invaluable technique that is seeing increased use. THG73 is an amber suppressor tRNA used to incorporate > 100 residues at the UAG, amber stop codon, in Xenopus oocytes. We have found that yeast Phe frameshift suppressors (YFFS) can incorporate UAAs at the CGGG and GGGU quadruplet codons in vitro and in vivo, allowing simultaneous incorporation of three UAAs in the nicotinic acetylcholine receptor (nAChR). The YFFS are more “orthogonal” than the amber suppressor tRNA, THG73, but the frameshift suppressors incorporate UAAs less efficiently than THG73. A library of tRNAs derived from THG73 has produced an amber suppressor that is “orthogonal” and suppresses similarly to THG73. An analogous opal suppressor tRNA allows incorporation of UAAs at the UGA, opal stop codon. The use of the amb...
In this work, we consider the numerical calculation of water waves in three dimensions. One well accepted method for studying surface waves is the boundary integral method, which defines the fluid velocities at the interface in terms of integrals over the boundary of the domain in which the problem is posed. There exists a considerable body of work on the numerical study of surface waves in two dimensions. However, until recently the numerical study of surface waves was considered intractable because of the high computational cost of approximating the defining integrals.
We discuss the boundary integral formulation for the three-dimensional water wave problem and present the point vortex approximation to the singular integrals which define the particle velocities. We consider three aspects of the point vortex approximation: accuracy o...
NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.
The noncatalyzed aldol addition of [...]-methylsilacyclobutane-[...],[...]-ketene acetals to aldehydes and the transformation of alkylated pseudoephedrine amides to highly enantiomerically enriched carboxylic acids and ketones are described. In Chapter 1, constraining of the silicon atom of an [...]-silyl ketene-[...],[...]-acetal within a four-membered ring is shown to greatly accelerate the rate of its noncatalyzed aldol addition to aldehydes and ketones. This reaction is highly syn selective and is proposed to proceed through a boat transition state involving pentacoordinate silicon. In Chapter 2, the preparation of carboxylic acids and ketones from alkylated pseudoephedrine amides is described. Acidic, basic, and slig...
