Varian Associates

About: Varian Associates is a(n) based out in . It is known for research contribution in the topic(s): Beam (structure) & Amplifier. The organization has 2160 authors who have published 2591 publication(s) receiving 46002 citation(s).

Adiabatic pulses for wideband inversion and broadband decoupling

Abstract: An inversion pulse for wideband application is obtained from a simple nonlinear amplitude modulation wherein the amplitude is modulated in accord with A(t)=A 0 {1-| sin βt| n } and the entire pulse is frequency modulated such that the phase varies as φ(t)=φ 0 +1/2 kt 2

Unconventional electronic structure evolution with hole doping in Bi2Sr2CaCu2O8+ delta : Angle-resolved photoemission results.

Abstract: We report angle-resolved photoemission results on ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{Dy}}_{x}{\mathrm{Cu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ and oxygen depleted ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ investigating the electronic structure changes above ${T}_{c}$ in materials with hole doping levels ranging from insulating to slightly overdoped. Near optimal hole doping, the Fermi surface is large and consistent with band calculations. In underdoped samples with ${T}_{c}$ of 60--70 K, portions of this Fermi surface are not seen. This change is related to the opening of an energy gap near $(\ensuremath{\pi},0)$ above ${T}_{c}$.

Field amplified sample injection in high-performance capillary electrophoresis

Abstract: A simple on-column concentration technique in high-performance capillary electrophoresis (HPCE) is reported. In conventional electro-injection in HPCE, samples are prepared in a buffer solution which has the same concentration as that inside the capillary column. The amount of ions injected into the column under this condition is limited. By preparing samples in a low-conductivity solution, e.g., water, and injecting the sample solution electroosmotically into the column, one can achieve a field enhancement at the injection point. The amount of ions injected will then be proportional to this enhancement factor. However, if one samples by switching the column directly from the high-conductivity buffer reservoir to the low-conductivity sample solution, the buffer boundary at the end of the column is disturbed and the electric field at the injection point might not be amplified properly. By injecting a short plug of water before sample introduction, one can provide a high electric field strength from the beginning of the injection. Several hundred-fold enhancements in the amount of injection were confirmed experimentally.

Indirect detection of magnetic resonance by heteronuclear two-dimensional spectroscopy

Abstract: A method is disclosed for highly sensitive indirect detection of nuclear magnetic resonance of nuclei having a low gyromagnetic ratio using pulse techniques. The method employs a coherent transfer of transverse magnetization from the nuclei of interest to nuclei of high gyromagnetic ratio for which the free induction decay, S (t 2 ), is observed as a function of the length of the time interval, t 1 , between imposition of transverse magnetization upon the nuclei of interest and transfer of magnetization to the observed nuclei. Contribution to the observed resonances not arising from the transferred transverse magnetization is eliminated and the resulting function S (t 1 , t 2 ) is double Fourier transformed to the frequency domain and displayed as a two dimensional plot for resolving the multiplet spectral structure of the spectra of the nuclei having such low gyromagnetic ratio.