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.

Photoemitter having a p-type semiconductive substrate overlaid with cesium and n-type cesium oxide layers

Abstract: A junction-type photoemitter is disclosed. The photoemitter includes a heavily doped P-type semiconductive substrate for absorbing photons of radiation to be converted into electrons to be emitted. An alkali metal layer such as cesium metal is formed over the substrate member for filling the surface energy states of the P-semiconductive substrate. Finally, a layer of cesium oxide is formed over the alkali metal layer to provide a low-work function surface facing the vacuum into which the electrons are emitted from the photoemitter. The substrate member may be made of a III-V compound semiconductor or an alloy of two different III-V compound semiconductors (each compound semiconductor including one element from the third group of Periodic Table and another element of the fifth group of the Periodic Table) to provide a semiconductive band-gap energy which is equal to or slightly more than the work function of the cesium oxide layer. The P-type semiconductive substrate member is heavily doped with a concentration of acceptor dopant greater than 3 X 1018 acceptors per cubic centimeter. Likewise, the cesium oxide layer is heavily doped with donor atoms of cesium to provide the relatively low-work function characteristic of such material. In a preferred embodiment, the P-semiconductive substrate is formed of InP or an alloy of InP and InAs. The photoemitter has improved conversion efficiency in the wavelength range from 0.5 microns to 1.37 microns wavelength.

Natural abundance 13C NMR studies of perezone and derivatives

Abstract: Assignment of all 13C chemical shifts of perezone (1) and some derivatives was possible using time averaged 25·15 MHz spectra with the aid of proton noise modulated and CW decoupling. Rapid interconversion of tautomeric forms of 2,5-dihydroxy-1,4-benzoquinones is deduced from the 13C spectra.

Fast NMR acquisition processor

Abstract: A Fourier transform NMR spectrometer incorporates a digital acquisition processor which provides a sequence of gating states specifying properties of the excitation, decoupling, and homogeneity spoiling pulses, lock channel operation and the like. Each gating state, together with the selected persistance time for the corresponding state, occupies one of a sequence of words supplied by the acquisition processor to a FIFO buffer. Timing control means, initialized from the persistance time portion of the current FIFO word, determines the time interval during which said gating state information is available at an output port, after which the next sequential FIFO word is advanced to the output port. NMR response is accumulated and averaged in a dual port fast semiconductor memory. The semiconductor memory is independently accessible to a host computer through a direct memory port. After each data block of a predetermined number of transients has been so processed, the entire updated cumulative spectrum is copied into non-volatile storage to secure the data against loss or distortion.

Septumless jet stream on-column injector for chromatography

Abstract: A plunger seats in the outlet end of a cavity formed in an injector housing. The plunger is moveable within the cavity between seated engagement with the outlet end and a position which permits fluid to flow out the outlet end. The cavity is sealed to withstand pressures on the order of 2000 bar. A groove formed in the wall of the plunger or in the wall of the cavity receives liquid sample from a sample feed line which is formed in the body of the housing and terminates adjacent the groove when the plunger is seated in the outlet end of the cavity. A source of mobile phase fluid is connected to the upper end of the cavity by an inlet line. By external displacement means, the plunger is moved out of seated engagement within said cavity to permit a jet stream of mobile phase fluid to sweep the sample from the sample groove out through the outlet end of the cavity and onto a chromatographic column connected to the injector housing.

Electrographic writing head of plural printed circuit construction

Abstract: An electrographic writing head is disclosed which employs a plurality of elongated flexible printed circuit boards each supporting thereon a portion of an array of closely spaced electrographic styli. Each circuit board is tapered from a wide end to a relatively narrow end. The narrow ends of the boards are arranged in side-by-side coplanar relation to define the exposed styli electrodes, whereas the wide ends of the boards contain the terminals for connecting to electrical connector assemblies, such wide ends being arranged in noncoplanar overlapping relation to accommodate connector assemblies.