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Quadrature LC VCO with passive coupling and phase combining network
A circuit and method for generating a signal is disclosed. The circuit includes a set of wide tuning LC tanks, a set of core transistors cross coupled to the set of wide tuning LC tanks, and a combining network coupled to the set of wide tuning LC tanks and the set of core transistors. The combining network further includes a set of inputs connected to the set of wide tuning LC tanks and the set of core transistors, a set of coupling transistors connected to the set of inputs, a set of source inductors connected to the set of coupling transistors, a coupling capacitor connected to the set of source inductors, a load resistor connected to the coupling capacitor. The combining network combines the set of inputs and the signal is delivered to the load resistor as a fourth order harmonic.Board of Regents, University of Texas Syste
Cytological and molecular characterization of wheat lines with Thinopyrum intermedium chromosome additions, substitutions and translocations resistant to barley yellow dwarf virus
Barley yellow dwarf virus (BYDV) is the most serious viral disease affecting wheat and genes for BYDV resistance have not been found in wheat. BYDV-resistant alien addition and alien substitution lines produced from a wheat × Thinopyrum intermedium (species of Agropyron complex) cross were characterized. Chromosome pairing in the hybrids between two substitution lines showed that they had the same Th. intermedium chromosome. Likewise, two addition lines involved the same alien chromosome. In situ hybridization of chromosomes, confirmed that line P29 is a disomic substitution line. Double monosomic seeds and self-pollinated seeds from monosomic addition plants were irradiated to induce translocations between wheat and Th. intermedium chromosomes. Putative translocations were selected on the basis of BYDV resistance and studied by chromosome analysis, Southern hybridization using Thinopyrum specific probe and RFLP markers. A BYDV-resistant translocation was identified
Electronic structure of turbostratic graphene
We explore the rotational degree of freedom between graphene layers via the
simple prototype of the graphene twist bilayer, i.e., two layers rotated by
some angle . It is shown that, due to the weak interaction between
graphene layers, many features of this system can be understood by interference
conditions between the quantum states of the two layers, mathematically
expressed as Diophantine problems. Based on this general analysis we
demonstrate that while the Dirac cones from each layer are always effectively
degenerate, the Fermi velocity of the Dirac cones decreases as ; the form we derive for agrees with that found via a
continuum approximation in Phys. Rev. Lett., 99:256802, 2007. From tight
binding calculations for structures with we
find agreement with this formula for . In contrast, for
this formula breaks down and the Dirac bands become
strongly warped as the limit is approached. For an ideal system
of twisted layers the limit as is singular as for the Dirac point is fourfold degenerate, while at one has the
twofold degeneracy of the stacked bilayer. Interestingly, in this limit
the electronic properties are in an essential way determined \emph{globally},
in contrast to the 'nearsightedness' [W. Kohn. Phys. Rev. Lett., 76:3168,
1996.] of electronic structure generally found in condensed matter.Comment: Article as to be published in Phys. Rev B. Main changes: K-point
mapping tables fixed, several changes to presentation
Succession of Mycoflora on Finished Leathers During Storage
The succession of mycoflora on ten important types of variously tanned finished leathers has been studied in storage. A number of fungi responsible for its deterioration have been recorded. High number of species was obtained in the samples stored at 90% RH at 28degree centigrade in comparison to leathers stored in laboratory conditions(40-60%RH and 28 degree centigrade). Some interesting fungi, namely, A. flavus (Black sclerotial isolate), A. Sydowivar. 2,P citrinum, P. simplicissimum and P. purpurogenum str. 2 were recorded on leathers for the first time as chrome loving fungi. The moisture content of leather samples stored at 90% RH was found to increase considerably after 60 days
Utilization of Fatliquors by Fungi
wenty five fungi isolated from deteriorated finished leathers have been tested to know their relative capacity to utilize the fatliquors viz., raw fish oil, castor oil, fish oil (sulphated), spindle oil turkey red oil and coconut oil. All these fatty substances supported the growth of all the fungi except a few species of Aspergillus, Trichoderma and Drechslera which showed moderate growth. The studies support the contention that fatliquors initially provide a substrate for the growth of fungi on finished leather and its products
Three-dimensional turbopump flowfield analysis
A program was conducted to develop a flow prediction method applicable to rocket turbopumps. The complex nature of a flowfield in turbopumps is described and examples of flowfields are discussed to illustrate that physics based models and analytical calculation procedures based on computational fluid dynamics (CFD) are needed to develop reliable design procedures for turbopumps. A CFD code developed at NASA ARC was used as the base code. The turbulence model and boundary conditions in the base code were modified, respectively, to: (1) compute transitional flows and account for extra rates of strain, e.g., rotation; and (2) compute surface heat transfer coefficients and allow computation through multistage turbomachines. Benchmark quality data from two and three-dimensional cascades were used to verify the code. The predictive capabilities of the present CFD code were demonstrated by computing the flow through a radial impeller and a multistage axial flow turbine. Results of the program indicate that the present code operated in a two-dimensional mode is a cost effective alternative to full three-dimensional calculations, and that it permits realistic predictions of unsteady loadings and losses for multistage machines
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