We have developed a
new theory of high temperature superconductivity based on the formation of inter-band
Cooper pairs. With new ab initio band structure calculations, we show that
the Cu x2-y2 and z2 bands have a symmetry allowed
crossing which occurs at the Fermi level for optimally doped La1.85Sr0.15CuO4.
This unique characteristic makes formation of inter-band Cooper pairs possible.
With this new band structure, we explicitly calculate the Cu and O NMR spin
relaxation and Knight shifts, the mid-IR absorption, the neutron scattering, and the ARPES
background signal. We also make arguments for the d-wave Josephson tunneling, the ARPES
pseudogap, the Hall effect, the resistivity, the XAS, the sensitivity of superconductivity
to doping, and the behavior of other high temperature superconductors. This new
theory is able to explain all of these sometimes bizarre phenomena in terms which are
simpler and more far reaching than ever proposed. More detail appears in the above
link and in our publications.
We have had a number of
projects for Chevron, including the construction of a new kinetic model for their gasoline
reforming process. This process is used to boost the octane rating of
gasoline and involves a complex catalytic network of reactions. The model is based
on thermochemical data derived from ab initio calculations and is simpler than
most as a result of a careful lumping strategy. Only seven adjustable parameters
(which are clearly tied to the function of the catalyst) are required. These
parameters were fit to experimental data for a C6 feed and the model was tested for
robustness against C7 and C8 feeds. Chevron now uses the model to set conditions for
its reactor. In addition to other projects for Chevron, we are currently developing
a similar model for paraffin hydrocracking. This work was done in collaboration with
the Materials Simulation Center at Caltech.
Medical Devices:
We assisted a multidisciplinary team
at LifeChart.com (formerly Enact Health Management Systems) to develop the AirWatch Asthma
Monitor. Our original contribution for LifeChart's novel spirometer was to incorporate
turbulent effects in the initial 100 milliseconds of airflow. This allowed the AirWatch to
meet FDA accuracy requirements for Peak Flow (PEF) and Force Expiratory Volume in one
second (FEV1). The resulting device is in use by tens of thousands of asthmatic children
and adults. To meet newer more stringent FDA requirements we were called in again to
extend the model. This led to an entirely new solution, derived by sequential application
of dimensional analysis, optimized by experimental observations. The resulting code is
simpler, more memory efficient, and faster to execute. The model has greater dynamic
response and has potential to detect subtle additional effects in the breath that address
important medical objections to the home use of spirometers. The new algorithms have
satisfied the latest FDA requirements.
Transition Metal Chemistry:
A number of our major
proprietary projects have involved the chemistry of transition metals. On the
academic front, we have had a long standing collaboration with Mike Bowers of UCSB to
characterize the gas phase reactions of transition metal ions with hydrocarbons. The
use of ab initio methods to aid in the interpretation of mass spectra has become
the standard in this field. Recent work has focused on the reactions of Ti+
with up to four CH4's, and the reactions of CoCp+ with multiple H2's
and CH4's. The latter gave the surprising result that the Cp ring did not
behave as a spectator ligand but was an active participant in the mechanism for
dehydrogenation of CH4. See our publications for
more information.
Radar Signal Processing:
We have modeled the
performance of space-time adaptive processing (STAP) and displaced phase-center antenna
(DPCA) algorithms for space-based and airborne ground moving target indication (GMTI)
radars; analyzed and developed models for clutter suppression, minimum detectable
velocity, area coverage rate, on-board processing versus communications trade-offs, and
the selection of pulse repetition frequency (PRF) for general STAP versus simpler DPCA
methods. In addition, we have worked on calibration and verification for the four civilian
space-based synthetic aperture radar (SAR) satellites currently in use (RADARSAT 1, ERS 1
& 2, JERS). This work was done in collaboration with Raytheon (RITSS), Jet Propulsion
Labs, Alaska SAR Facility, and Usersystems, Inc.
Proprietary Contract Research:
Henkel Corporation: Homogeneous catalysis
Rhône-Poulenc Ag: Photostability of pesticides
Rhône-Poulenc Rorer:
Pharmaceuticals