Michael Hess

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We present the first science results from the Keck Interferometer, a direct-detection infrared interferometer utilizing the two 10-meter Keck telescopes. The instrument and system components are briefly described. We then present observations of the T Tauri object DG Tau, which is resolved by the interferometer. The resolved component has a radius of 0.12(More)
In this paper we present an inversion algorithm for nonlinear ill-posed problems arising in atmospheric remote sensing. The proposed method is the iteratively regularized Gauss–Newton method. The dependence of the performance and behaviour of the algorithm on the choice of the regularization matrices and sequences of regularization parameters is studied by(More)
The detection of low signature or camouflaged targets in cluttered backgrounds is a crucial problem in tactical reconnaissance. In the past few years, imaging spectral and polarimetric sensors have been evaluated for this application. Although these sensors have separately generated promising results, each imaging modality alone appears to have not achieved(More)
High-capacity anode materials for lithium ion batteries (LIBs), such as spinel-type metal oxides, generally suffer from poor Li(+) and e(-) conductivities. Their drastic crystal structure and volume changes, as a result of the conversion reaction mechanism with Li, severely impede the high-rate and cyclability performance toward their practical application.(More)
The iteratively regularized Gauss–Newton algorithm with simple bounds on the variables is extended to the multi-parameter case. The global regularization matrix is computed by using the L-curve method for a sequence of one-parameter regularization problems. Numerical results concerning the joint retrieval of O3 and NO2 profiles using the scattered light(More)
We present an operando study of a lithium ion battery combining scanning X-ray diffraction (SXRD) and synchrotron radiation X-ray tomographic microscopy (SRXTM) simultaneously for the first time. This combination of techniques facilitates the investigation of dynamic processes in lithium ion batteries containing amorphous and/or weakly attenuating active(More)
This paper describes the design, realization and operation of a prototype liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the development of a novel online monitoring and calibration system exploiting UV laser beams. In particular, the system is intended to measure the lifetime of the primary ionization in LAr, in turn related to the(More)
The Keck Interferometer (KI) combined the two 10 m W. M. Keck Observatory telescopes on Mauna Kea, Hawaii, as a long-baseline nearand mid-infrared interferometer. Funded by NASA, it operated from 2001 until 2012. KI used adaptive optics on the two Keck telescopes to correct the individual wavefronts, as well as active fringe tracking in all modes for(More)