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.

Sample delivery system used in chemical analysis methods which employs pressurized gas for sample conveyance

Abstract: A sample delivery system for a flow-through NMR analysis is provided, which utilizes pressurized gas as a means for conveying a sample into and out of an NMR spectrometer. Two sources of gas pressure, a forward pressure and back pressure, oppose the sample within the tubing of the sample delivery system and the tubing of the flow-through system which are operatively coupled together. Conveyance of the sample in any direction within the tubing is achieved by adjusting the pressure differential. Precise positioning of the sample in the magnetic field center and complete removal of the sample from the NMR spectrometer when analysis is complete are achieved by using a signal processor which receives signals from the NMR detector or other detectors positioned along the length of the tubing. These signals provide an indication of the position of the sample in the tubing. The signal processor uses this information to adjust the forward and back pressure, thereby achieving the desired positioning of the sample.

Modeling broad-area DBR/DFB lasers

Abstract: A variety of broad-area semiconductor laser devices are currently providing high-power with near diffraction-limited performance. These new devices share an important design element: the suppression of filamentation tendencies. Specific designs include traveling-wave amplifiers and reflective-wave amplifiers, tapered amplifiers, unstable resonator oscillators and most recently, curved or angled grating DBR/DFB oscillators. These latter designs offer the advantages of filament suppression and angular spectrum filtering, while providing strong spectral filtering as well. We review the motivation and design principles for several of the new broad-area DBR/DFB devices and describe the algorithms that have been developed in order to provide accurate numerical simulations and performance predictions.

Gain characteristics of stagger-tuned multicavity gyroklystron amplifiers

Abstract: A linear theory of gyroklystron amplifiers has been formulated by solving an integral differential equation describing self-consistent gyrotron interaction in a series of cavities coupled by cutoff drift tubes. One can evaluate the gain versus frequency characteristics of gyroklystron designs which allow both mechanical and magnetic tuning of cavities.

Field amplified polarity switching sample injection in capillary zone electrophoresis

Abstract: An improved electroinjection method of introducing a sample having positive and negative ions into a capillary column for CE or CZE process by introducing a short plug of a low concentration buffer before introducing the sample into the column which results in increasing amount of charged ions of the sample introduced in the capillary column due to increasing the electric field at the injection point. A method for efficiently introducing both positive and negative ions is also shown.