Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Wafer. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

Bonded phase chromatographic supports.

Abstract: Functionalization of particulate bonded phase chromatographic supports prepared by silanization of silica gel or controlled pore glass and containing pendant primary alkyl amine groups. Functionalization results from the activation of the amines by reaction with N,N'-carbonyldiimidazole (CDI), or a related azolide, in anhydrous organic solvent, followed by derivatization of the support. Derivatization results from reaction of the activated support with a functionalizing reagent consisting of a primary or secondary, alkyl or aryl amine in organic solvent, or from an aqueous solution of the amine or its salt. A urea linkage results through which the functionalizing reagent is covalently attached to the support. Derivatization can result from the addition of an excess of a single reagent, or as a consequence of the sequential addition of two or more functionalizing reagents. Chromatographic supports preparation in this manner yield materials suitable for affinity, covalent, ion exchange and hydrophobic interaction chromatography of biomolecules as well as for the preparation of immobilized reagents.

High-Frequency Electrodynamics of Bi 2 Sr 2 CaCu 2 O 8+δ : Nonlinear Response in the Vortex State

Abstract: Coherent terahertz spectroscopy is used to measure the complex conductivity of thin films of ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ in the vortex state as a function of frequency, temperature, and applied magnetic field. We report an unusual sublinear power law dependence of the high-frequency magnetoconductivity $\ensuremath{\Delta}\ensuremath{\sigma}(H)\ensuremath{\equiv}\ensuremath{\sigma}(H)\ensuremath{-}\ensuremath{\sigma}(0)$ on magnetic field. Over a broad range of field and temperature, $\ensuremath{\Delta}{\ensuremath{\sigma}}_{2}$ varies as ${H}^{\ensuremath{\alpha}}$, with $\ensuremath{\alpha}\ensuremath{\approx}\frac{1}{2}$. We present a model based on the nonlinear London electrodynamics predicted for a $d$-wave superconductor which quantitatively explains these results using only parameters obtained from zero-field measurements.

Calculations of chemical shifts

Abstract: Electric field theory is used to predict the 1H, 13C and 19F chemical shifts of a series of halogenated ethanes and the 19F shifts of some cyclobutanes. The quantity 3PI/r 6 is used to describe the time-averaged square of the electric field at the nucleus from fluctuating point-dipoles elsewhere in the molecule. The results are compared with predictions made by an alternative method, using P/Ir 3, to define the electric fields. The calculations show that, whatever the theoretical justification or lack of it, the former quantity is often more widely applicable than the latter.

Zero deflection magnetically-suppressed Faraday for ion implanters

Abstract: A magnetically suppressed Faraday system for use in an ion beam treatment system, such as an ion implanter, includes a Faraday cage defining a chamber having an entrance, and a magnetic suppression assembly positioned at the entrance of the chamber. The downstream end of the Faraday cage is positioned adjacent to a workpiece such as a semiconductor wafer. The magnetic suppression assembly includes a suppression magnet structure for producing suppression magnetic fields of sufficient strength to inhibit escape of electrons from the chamber, a field cancellation magnet structure for producing cancellation magnetic fields for substantially canceling magnetic fields, produced by other magnets in the magnetic suppression assembly, near the downstream end of the chamber, and an angle correction magnet structure for producing angle correction magnetic fields selected such that the ion beam is subjected to zero or nearly zero net angular deflection as it passes through the Faraday system.

Optical detection system for capillary separation columns

Abstract: On-column optical detection apparatus and method for use with capillary separation columns are shown. The apparatus and method minimize the adverse effects of light scattered from the walls of the column, thereby improving detection sensitivity and providing greater dynamic range. Light from a conventional source is focussed onto a column. Spatial filter means are positioned in front of the column to prevent at least some light from striking the column wall. Another spatial filter is positioned in front of a light collecting means which gathers light emanating from the column. In a specific embodiment, a unique monolens design is shown comprising collecting and focussing lens formed as an integral unit with a bore for a capillary column.