Varian Associates

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

Gyromagnetic resonance spectrometer utilizing an improved sample spinning and ejecting structure

Abstract: A gyromagnetic resonance spectrometer employing a turbine affixed to a sample holder and responsive to a flow of air for spinning the sample under investigation in the magnetic field, the turbine floating on a column of air within a fixed stator or housing structure, is described. Air bearings are provided for the rotating sample holder within the stator or housing. Means is provided for blocking the egress of the air from the air bearings to eject the sample holder from the magnetic field.

High-resolution nmr investigation of base pairing structure of transfer rna *

Abstract: In most previous nmr studies of transfer RNA, the samples were dissolved in D,O rather than water to akoid the overwhelming problems usually caused by the water res0nance.l-3 Although this may have been unavoidable it was unfortunate, since resonances from exchangeable protons in the tRNA are lost and these turn out to be extremely interesting. Several years ago we found that high field nmr spectrometers (220 and 300 MHz) could be used with H,O solutions of tRNA, and thereby discovered a set of low field resonances resulting from hydrogen-bonded protons of tRNA.'. j In a series of studies,'-' we have established that these resonances are due to the GN, protons of GC base pairs and UN, protons of AU base pairs (FIGURE 1 ) . Since only one such resonance appears in the low field region (-1 1 to -15 ppm) for each base pair, it was immediately evident that low field nmr spectra could provide detailed information about the base pairing structure of tRNA and other polynucleotides in solution. Some indication of the high information content of these low field nmr spectra of tRNA is provided by the high resolution nmr spectra shown in FIGURE 2. From integration of these spectra, it is possible to determine the number of base pairs in the molecule and this certainly provides useful information about the structure of these molecules in solution. However, it is evident that the resonances associated with the different GC and AU base pairs exhibit a wide range of chemical shifts, and our major effort during the past year has been to determine the factors responsible for the shifts so that resonances could be assigned to individual base pairs. In this paper we summarize the results of our efforts to date.

In 0.53 Ga 0.47 As submicrometer FET's Grown by MBE

Abstract: We describe the fabrication process for InGaAs submicrometer gate JFET's, using Be ion implantation and wet chemical etching. A gate length as small as 0.5 µm can be formed by this technique. Such FET's made on MBE-grown material bad a dc trans-conductance as high as 85 mS/mm and showed a high power-handling capability.