Injection Locked Millimeter Wave Oscillators at Ka, V, and W-Bands

Injection locked Gunn oscillators have been developed to amplify the upconverted millimeter wave frequencies. They are being used in millimeter wave communication systems at Ka, V and W-Bands respectively.     

Functoriality for the exterior square of

In this paper we prove the functoriality of the exterior square of cusp forms on as automorphic forms on and the symmetric fourth of cusp forms on as automorphic forms on . We prove these by applying a converse theorem of Cogdell and Piatetski-Shapiro to analytic properties of certain -functions obtained by the Langlands-Shahidi method. We give several applications: First, we prove the weak Ramanujan property of cuspidal representations of and the absolute convergence of the exterior square -functions of . Second, we prove that the fourth symmetric power -functions of cuspidal representations of are entire, except for those of dihedral and tetrahedral type. Third, we prove the bound for Hecke eigenvalues of Maass forms over any number field.

     

Vibrational spectral studies of L-methionine L-methioninium perchlorate monohydrate

The infrared and laser Raman spectra of L-methionine L-methioninium perchlorate monohydrate were recorded at room temperature and the vibrational assignments of the observed wave numbers were made. The presence of both the carbonyl and the ionized carboxylic groups has been identified in the title complex. The L-methionine and L-methioninium the cation have different conformations. This together with the different environment has seen by the two -CH(2)- groups in each skeleton cause several of the group wave numbers to occur as doublets or as broad bands. The perchlorate anion was found to be in the T(d) symmetry in the methionine environment. The coordination to other ligands in the crystal through hydrogen bonding does not affect this symmetry. The extensive intermolecular hydrogen bonding in the crystal was identified by the shifting of bands due to the stretching and bending modes of the various functional groups. Fermi resonance has also been observed.     

Thienoquinolines: X—The fragmentation of thieno(2,3-b)quinoline and its derivatives under electron impact

A study has been made of the fragmentation upon electron impact of thieno(2,3-b)quinoline and sixteen of its derivatives containing methoxy, methylenedioxy, chloro, bromo, iodo, nitro and methyl substituents. Besides these, the fragmentation patterns of some S-oxides, and S,S-dioxides were also investigated. The majority of the spectra contain molecular ions and the principal fragmentation routes involve loss of carbon monosulphide and hydrogen cyanide from the molecular ion. Rearrangement of the molecular ion appears to precede the fragmentation process in the case of S,S-dioxides. The fragmentation of 4-methylthieno(2,3-b)quinoline is closely analogous to that of alkylquinolines. The main features of these spectra can be predicted from the fragmentation pathways proposed for the parent thieno(2,3-b)quinoline.     

Komplexe von Lanthanidnitraten mit 2-Methylpyridin-1-oxid

Complexes of lanthanide nitrates with 2-methylpyridine-1-oxide of the formuleLn(2-MePyO)₃(NO₃)₃ whereLn=Nd, Sm, Tb, Dy and Yb and La(2-MePyO)₃(NO₃)₃·2H₂O have been prepared and characterized by chemical analyses, IR spectral, conductance andDTA data. IR spectral data have been interpreted in terms of the coordination of the ligand to the metal through the oxygen of the N–O group. Conductance and IR spectral data show that all the nitrate groups are bidentate and that two of the nitrate groups are bound to the metal in a different manner than the other.     

A Predictive Approach Using Fractal Analysis for Analyte-Receptor Binding and Dissociation Kinetics for Surface Plasmon Resonance Biosensor Applications

A predictive approach using fractal analysis is presented for analyte-receptor binding and dissociation kinetics for biosensor applications. Data taken from the literature may be modeled, in the case of binding using a single-fractal analysis or a dual-fractal analysis. The dual-fractal analysis represents a change in the binding mechanism as the reaction progresses on the surface. A single-fractal analysis is adequate to model the dissociation kinetics in the examples presented. Predictive relationships developed for the binding and the affinity (k(diss)/k(bind)) as a function of the analyte concentration are of particular value since they provide a means by which the binding and the affinity rate coefficients may be manipulated. Relationships are also presented for the binding and the dissociation rate coefficients and for the affinity as a function of their corresponding fractal dimension, D(f), or the degree of heterogeneity that exists on the surface. When analyte-receptor binding or dissociation is involved, an increase in the heterogeneity on the surface (increase in D(f)) leads to an increase in the binding and in the dissociation rate coefficient. It is suggested that an increase in the degree of heterogeneity on the surface leads to an increase in the turbulence on the surface owing to the irregularities on the surface. This turbulence promotes mixing, minimizes diffusional limitations, and leads subsequently to an increase in the binding and in the dissociation rate coefficient. The binding and the dissociation rate coefficients are rather sensitive to the degree of heterogeneity, D(f,bind) (or D(f1)) and D(f,diss), respectively, that exists on the biosensor surface. For example, the order of dependence on D(f,bind) (or D(f1)) and D(f2) is 6.69 and 6.96 for k(bind,1) (or k(1)) and k(2), respectively, for the binding of 0.085 to 0.339 μM Fab fragment 48G7(L)48G7(H) in solution to p-nitrophenyl phosphonate (PNP) transition state analogue immobilized on a surface plasmon resonance (SPR) biosensor. The order of dependence on D(f,diss) (or D(f,d)) is 3.26 for the dissociation rate coefficient, k(diss), for the dissociation of the 48G7(L)48G7(H)-PNP complex from the SPR surface to the solution. The predictive relationships presented for the binding and the affinity as a function of the analyte concentration in solution provide further physical insights into the reactions on the surface and should assist in enhancing SPR biosensor performance. In general, the technique is applicable to other reactions occurring on different types of biosensor surfaces and other surfaces such as cell-surface reactions. Copyright 2000 Academic Press.     

Synthesis of 3-methyl-coumarins, -thiacoumarins and -carbostyrils

Reaction of 3,6-dimethyl-4-phenyl-3,4-dihydrocoumarin5a with anhydrous aluminum chloride gave 3,6-dimethyl-coumarin (6a); likewise, 6-chloro-3-methyl-coumarin (6b) was obtained from5b. Substituted 3-methyl-thiacoumarins (8a,b and 3-methyl-carbostyrils (10a-e) were prepared from the reactions of the respectivea-methyl-cinnamoyl derivatives (7a,b and (9a-e), of thiophenols and anilines.     

Infrared and laser Raman spectral studies of bis(dl-aspartic acid) sulfate

The infrared and Raman spectra of bis(dl-aspartic acid) sulfate in the crystalline state are recorded at room temperature and the vibrational assignments of the observed wavenumbers are made. The presence of two carbonyl (CO) groups has been identified in the title complex and the two carbonyl groups are in different environment. The extensive intermolecular hydrogen bonding in the crystal has been identified by the shifting of bands due to the stretching and bending modes of the various functional groups. The sulfate group forms the anion. Its fundamentals continue to be degenerate except for the asymmetric bending mode and it suggests that the T(d) symmetry of SO(4)(2-) group has not been affected in the crystal.     

Hyperbranched polyurethanes with varying spacer segments between the branching points

Hyperbranched polyurethanes, with varying oligoethyleneoxy spacer segments between the branching points, have been synthesized by a one-pot approach starting from the appropriately designed carbonyl azide that incorporates the different spacer segments. The structures of monomers and polymers were confirmed by IR and ¹H-NMR spectroscopy. The solution viscosity of the polymers suggested that they were of reasonably high molecular weight. Reversal of terminal functional groups was achieved by preparing the appropriate monohydroxy dicarbonyl azide monomer. The large number of terminal isocyanate groups at the chain ends of such hyperbranched macromolecules caused them to crosslink prior to its isolation. However, carrying out the polymerization in the presence of 1 equiv of a capping agent, such as an alcohol, resulted in soluble polymers with carbamate chain ends. Using a biphenyl-containing alcohol as a capping agent, we have also prepared novel hyperbranched polyurethanes with pendant mesogenic segments. These mesogen-containing polyurethanes, however, did not exhibit liquid crystallinity probably due to the wholly aromatic rigid polymer backbone. © 1996 John Wiley & Sons, Inc.