Novel 53/106 GHz Dual-Band MMW LC Oscillator Implemented in SiGe BiCMOS Technology

In this Paper, we present a fully integrated millimeter wave LC voltage-controlled oscillator (VCO), which employs a novel topology, operating at dual-band frequency of 53.22 GHz-band and 106.44 GHz-band. The low-phase noise performance of –107.3 dBc/Hz and –106.1 dBc/Hz at the offset frequency of 600 kHz, –111.8 dBc/Hz and –110.6 dBc/Hz at the offset frequency of 1 MHz around 53.22 GHz and 106.44 GHz are achieved using IBM BiCMOS-6HP technology, respectively. Two tuning ranges, of 52.7 - 53.8 GHz and 105.4 - 107.6 GHz for the proposed LC VCO are obtained. The output voltage swing of this VCO is around 1.8 V_p-p at the operation frequency of 53.22 GHz and 0.45 V_p-p at 106.44 GHz; the total power consumption is about 16.5 mW. To our knowledge, this is the first oscillator which operates at dual-band frequency above 50 GHz with the best preformance.     

The combined use of ab initio molecular orbital theory and matrix isolation infrared spectroscopy in the study of molecular interactions

The infrared spectra of a linear (C_s) and a cyclic (C_i) water dimer and a linear (C_s) and a cyclic (C_2h) ammonia dimer have been calculated, at the second order level of MØller-Plesset perturbation theory, using the 6-31G^** basis set. The calculated spectra have been compared with the spectra of water and ammonia isolated in nitrogen and argon matrices. In the case of water, theory predicts the linear to be the more stable isomer, and the observed spectrum can only be interpreted in terms of the linear structure. For ammonia, while the experimentally determined spectrum fits the calculated spectrum of the linear dimer fairly closely, the prediction of which is the more stable structure is still ambiguous.     

The intramolecular Baylis-Hillman reaction: easy preparation of versatile substrates, facile reactions, and synthetic applications

We have developed a general and highly efficient method for the preparation of diverse [small omega]-formyl-[small alpha],[small beta]-unsaturated carbonyl compounds and optimized the conditions for the intramolecular Baylis-Hillman reactions of these compounds to provide various biologically important polycyclic compounds.     

A new imidazolium cavitand for the recognition of dicarboxylates

[structure: see text] A new cavitand bearing four imidazolium groups was synthesized for the recognition of anions through (C-H)+...X- hydrogen bond formation. The binding properties toward various anions including dicarboxylates were examined on the basis of 1H NMR spectroscopic experiments.     

Complexity of vector spin glasses

We study the annealed complexity of the m-vector spin glasses in the Sherrington-Kirkpatrick limit. The eigenvalue spectrum of the Hessian matrix of the Thouless-Anderson-Palmer free energy is found to consist of a continuous band of positive eigenvalues in addition to an isolated eigenvalue and (m-1) null eigenvalues due to rotational invariance. Rather surprisingly, the band does not extend to zero at any finite temperature. The isolated eigenvalue becomes zero in the thermodynamic limit, as in the Ising case (m=1), indicating that the same supersymmetry breaking recently found in Ising spin glasses occurs in vector spin glasses.     

Simulation studies of phase inversion in agitated vessels using a Monte Carlo technique

A speculative study on the conditions under which phase inversion occurs in agitated liquid-liquid dispersions is conducted using a Monte Carlo technique. The simulation is based on a stochastic model, which accounts for fundamental physical processes such as drop deformation, breakup, and coalescence, and utilizes the minimization of interfacial energy as a criterion for phase inversion. Profiles of the interfacial energy indicate that a steady-state equilibrium is reached after a sufficiently large number of random moves and that predictions are insensitive to initial drop conditions. The calculated phase inversion holdup is observed to increase with increasing density and viscosity ratio, and to decrease with increasing agitation speed for a fixed viscosity ratio. It is also observed that, for a fixed viscosity ratio, the phase inversion holdup remains constant for large enough agitation speeds. The proposed model is therefore capable of achieving reasonable qualitative agreement with general experimental trends and of reproducing key features observed experimentally. The results of this investigation indicate that this simple stochastic method could be the basis upon which more advanced models for predicting phase inversion behavior can be developed.     

A theoretical mode for the instability of turbulent boundary layer over compliant surface

A theoretical model for the instability of turbulent boundary layer over compliant surfaces is described. The investigation of instability is carried out from a time-asymptotic space-time perspective that classifies instabilities as either convective or absolute. Results are compared against experimental observations of surface waves on elastic and viscoelastic compliant layers.