We have developed an open source 3D, MATLAB based, resistivity inversion package. The forward solution to the governing partial differential equation is efficiently computed using a second-order finite volume discretization coupled with a preconditioned, biconjugate, stabilized gradient algorithm. Using the analytical solution to a potential field in a homogeneous half space, we evaluate the ac...

An integrated surface geophysical pilot study at the Texas A&M University Brazos River Hydrologic Field Research Site (BRHFRS), College Station, Texas, was done to determine the effectiveness of methods for defining the hydrostratigraphic framework and hydrogeologic properties for a ground-water availability model. Time-domain electromagnetic (TDEM) soundings and direct-current (2D–DC) resistiv...

The calculation of apparent resistivities, based on the model of a homogeneous half-space, is commonly the first step in Ž . order to evaluate helicopter electromagnetic HEM data. Due to the increase in frequencies used in HEM systems, survey results are not only displayed as apparent resistivity maps but also as cross-sections that require resistivity and depth information. After a brief descr...

Epitaxial Ag(001) layers were deposited on MgO(001) in order to study electron surface scattering. X-ray reflection indicates 3D layer nucleation with a high rms surface roughness of 1.0 nm for a layer thickness d1⁄4 3.5 nm. X-ray diffraction shows that f111g twins form at d< 11 nm, followed by 2nd generation twinning for 11 nm< d< 120 nm. Increasing the growth temperature from 25 to 150 C supp...

over the past three decades helicopter-borne electromagnetic (hem) measurements have been used to reveal the resistivity distribution of the earth&apos;s subsurface for a variety of applications. hem systems include a “bird” or sensor containing one or more pairs of transmitting and receiving coils. the separation between the rigidly mounted transmitting and receiving coils of a coil-pair typic...

An automatic inverse method has been developed for generating layered earth models from electrical sounding data. The models have the minimum number of layers required to fit a resistivity sounding curve or a combined resistivity and induced polarization sounding. The ground is modeled using a very large number of thin layers to accommodate arbitrary variations. The properties of the layers are...

This paper discusses modeling of non-uniform substrate resistivity for substrate resistance extraction. Though substrate resistivity of each substrate layer is frequently assumed to be uniform, doping profile of each substrate layer is not uniform. We present the extraction error of substrate resistance under uniform resistivity assumption. The resistivity models we suggest enable accurate resi...

We propose a new mechanism for surface-induced magnetic anisotropy to explain the thickness dependence of the Kondo resistivity of thin films of dilute magnetic alloys. The surface anisotropy energy, generated by spin-orbit coupling on the magnetic impurity itself, is an oscillating function of the distance d from the surface and decays as 1/d2. Numerical estimates based on simple models sugges...

We analyze the effect of the electron-electron interaction on the resistivity of a metal near a Pomeranchuk quantum phase transition (QPT). We show that umklapp processes are not effective near a QPT, and one must consider both interactions and disorder to obtain a finite and T dependent resistivity. By power counting, the correction to the residual resistivity at low T scales as AT((D+2)/3) ne...