WorldCat Identities


Works: 24 works in 52 publications in 1 language and 57 library holdings
Publication Timeline
Study of adsorption of gases on solids in the high vacuum range by C. M Bliven( Book )

5 editions published between 1962 and 1965 in English and held by 9 WorldCat member libraries worldwide

The work function of polycrystalline tungsten was measured, using the retarding field technique, as a func tion of the exposure to a carbon monoxide ambient. The work function was found to vary from 4.4 eV to 5.2 eV in going from an initially clean surface to one saturated with carbon monoxide. The successive adsorption of oxygen on a tungsten surface already saturated with carbon monoxide is inferred from the work-function data. The increase in work function (from 5.2 eV to 6.4 eV) is indicative of possibly a monolayer or more of adsorbed oxygen. The work functions for a clean (111) silicon surface, silicon exposed to 0.000003 torr-sec oxygen, and silicon exposed to 0.000009 torr-sec oxygen were found by the retarding field method to be 4.79 eV, 5.02 eV and 5.07 eV, respectively. (Author)
Studies of electron tube materials and thermionic emission processes( Book )

8 editions published between 1961 and 1963 in English and held by 8 WorldCat member libraries worldwide

The thermionic emission properties of ultra-pure nickel-base oxide cathodes in a clean test diode were investigated. The effects of electrolytic activation, life-test conditions and gas ambient on thermionic emission were evaluated. The emission properties of pure nickel-base cathodes are compared with cathodes containing known im purities in the base metal or the coating and the effects of these impurities on emission are evaluated. The influence of the anode on cathode activation is shown. Measurements of the sub limation from various metal-base oxide cathodes are described. A Knudsen cell mass spectrometer system was designed and assembled for the study of high-temperature reactions between tube materials. The Knudsen cell was operated in the mass spectrometer at temperatures up to 2600 K, and the system was calibrated on the basis of published data of vapor pressure versus tempera ture for pure silver. (Author)
Study of failure mechanisms in high power radio frequency generating devices( Book )

6 editions published between 1962 and 1964 in English and held by 6 WorldCat member libraries worldwide

This investigation undertakes to determine the causes of failures in gridded power traveling wave tubes. The gas ambient of two types of operating tubes and of individual tus sub assemblies and components are examined with an omegatron mass spectrometer permanently attached to the unit under test. Background gas ambients in envelopes containing only omegatrons are used as controls and are presented. Electrical test parameters of the traveling-wave tube in re lation to its gas ambient are presented and correlations are made with cathode activity decrease and power output decrease as functions of integrated partial gas pressures in th ating tube. Contributions made by various proc essed tube components to the gas ambient of the operating vacuum tube are presented and discussed. (Author)
Semiconductor microwave amplitude and phase modulator( Book )

3 editions published in 1965 in English and held by 3 WorldCat member libraries worldwide

Experiments on the amplitude modulator indicate a linear falloff of modulation depth with drive frequency from 12.5 percent at 0.9 Gc/s to 8.4 percent at 1.4 Gc/s. It appears from these data that the useful modulation bandwidth of this device in its present configuration falls in the 1 Gc/s range. The drive power required to maintain a constant modulation index as the rf carrier power was varied over a three to one range was experimentally determined. A linear relation existed between the drive and carrier power levels. Measurements indicate that the injecting point contact can be represented by a series LCR circuit in shunt with the transmission line. On the basis of this circuit, it is possible to explain the observed decrease in insertion loss with forward bias. The stability of the GaAs varactors was improved by coating the semiconductor surface with a thin film of epoxy. However, the yield was limited, and some electrical deterioration occurred immediately after application of the epoxy coating. (Author)
Experimental study of factors controlling the effectiveness of high-temperature protective coatings for tungsten by C. D Dickinson( Book )

4 editions published between 1963 and 1965 in English and held by 3 WorldCat member libraries worldwide

The restrictions imposed by the processes of diffusion, evaporation, and coating substrate reactions on the choice of potential protective coating materials for tungsten were studied analytically and experimentally. The diffusive restriction is the most limiting and eliminates many refractory oxides with otherwise satisfactory attributes. The diffusive properties of rare earth sesquioxides and complex refractory oxides were explored by means of oxidation experiments and a layer growth experiment respectively. Mass spectrometric studies of the vaporization of refractory complex oxides were carried out to determine the applicability of the Wagner-Hauffe method of predicting vaporization rates. Provided certain thermodynamic approximations are valid and the vapor species over the complex oxide are the same as those over the pure component oxides, the predictions yield order of magnitude accuracy. A survey and exploration of reactions of possible coating materials with tungsten was performed emphasizing promising materials from the diffusion studies. (Author)

2 editions published between 1965 and 1966 in English and held by 2 WorldCat member libraries worldwide

A program is being conducted to explore the application of known hot-carrier effects in semiconductors to the development of new and improved microwave devices. The devices being investigated include modulators, mixers, harmonic generators, and detectors. Modulation indices of redesigned hot-carrier amplitude modulators were measured up to modulation frequencies of 1600 MHz. Three units exhibited modulation indices between 30 and 55% at 1600 MHz, and between 70 and 75% at 250 MHz. A fourth unit exhibited essentially the same modulation depth at 1600 MHz as at 250 MHz, i.e., approximately 80%. An evaluation of hot-carrier mixer sensitivity using various high-quality InSb semiconductor samples and several fabrication techniques is summarized. Experimental data are presented on the conversion loss and i.f resistance of the cooled InSb hot-carrier mixer as a function of local oscillator power level. The i.f. resistance of a hot-carrier mixer and a Schottky barrier mixer are compared as a function of local oscillator power. A theoretical analysis is presented which extends the range of validity of the so-called dc incremental method and the amplitude modulation method of measuring the conversion loss of a mixer. With peak input power on the order of 100 watts, the conversion efficiency of the harmonic generator is approximately -60 dB. (Author)
Development of improved gallium arsenide point contact varactor diodes for operation at x-band and above( Book )

1 edition published in 1962 in English and held by 2 WorldCat member libraries worldwide

Hot carrier phenomena in semiconductors at microwave frequencies( Book )

2 editions published in 1962 in English and held by 2 WorldCat member libraries worldwide

The possibility of achieving amplification of microwaves by means of hot electrons in InSb with an applied magnetic field was investigated with the use of the simple model of the and structure. Preliminary results indicate the possibility of obtaining amplification of circularly polarized plane microwaves using a bulk semiconductor such as InSb with two carriers and steady axial magnetic and electric fields. Probe measurements were made to detect phonons emitted by hot electrons in adjacent field-free regions in n-type Ge. High levels of spurious voltage pickup masked any phonon-drag effect that may have been present. small-signal measurements of conductivity and dielectric constant at 69.25 kmc as functions of dc bias field were made on one InSb sample. Very strong field dependence was observed, and it appears that this material may be appicable to variable-reactance devices at submillimeter wavelengths. Largesignal experiments were also performed in which the InSb sample was made to function as a bolometer-type peak power detector at 69.25 kmc. A hot-carrier mixer was constructed which will be used to measure the extent to which the heating of the carriers follows the field at 24 kmc. (Author)
Nonlinear semiconductors at millimeter frequencies( Book )

2 editions published in 1965 in English and held by 2 WorldCat member libraries worldwide

Measurements of the noise figure of an experimental 70-Gc/s receiver incorporating InSb hot-carrier mixers at 77 K were undertaken. The initial results indicate that the noise figure of this receiver is approximately 6 dB higher than that of the same receiver using a Schottky barrier mixer at room temperature. A 70-Gc/s hotcarrier detector was designed and constructed which exhibited square-law behavior for rf power levels up to 5 mW. A reliable experimental technique for measuring the characteristics of the hot-carrier modulator at uhf was established. Measurements on a typical unit yielded modulation indices of 80 percent at 220 Mc/s and 40 percent at 400 Mc/s. The insertion loss of the modulator was 4.5 dB. (Author)
Study of thin film compounds formed from simultaneously evaporated constituents( Book )

2 editions published between 1962 and 1965 in English and held by 2 WorldCat member libraries worldwide

Thin films of lead titanate suitable for forming thinfilm capacitors have been prepared by the simultaneous evaporation of lead and titanium oxides in an oxygen atmosphere. The experimental conditions for deposition of the films on silicon substrates have been established for obtaining virtually a 100 percent yield of films with a specific capacitance greater than 1 micro F/sq cm, dielectric constants in the range from 200 to 400, and a dissipation factor less than 10 percent. This high reproducibility derives from an improved understanding and control of the vapor-phase oxidation of titanium and of the interactions between the dielectric film and the metal electrodes. The current procedure for synthesis of the lead titanate films is given in detail. An Appendix provides a survey of the literature on previous work on highdielectric-constant films with the perovskite structure. (Author)

2 editions published between 1967 and 1968 in English and held by 2 WorldCat member libraries worldwide

The study of high-energy liquid lasers was approached from three aspects: device, material, and optical. Two systems for circulation of the liquid medium in an operating laser were designed and constructed, and one was operated successfully. Problems concerning the optical homogeneity of the laser solution and mechanical abrasion of the pump parts remain to be solved. Most problems of materials preparation were overcome and high-quality solutions can now be prepared reproducibly. Spectroscopic and optical measurements were made, and the transition cross-section for the laser emission was calculated. The emission of the laser was studied in terms of energy output, spectral line breadth, divergence, amplification, and a new phenomenon, self Q-switching. (Author)

2 editions published between 1962 and 1963 in English and held by 2 WorldCat member libraries worldwide

The theoretical performance of an idealized equivalent mixer circuit, with short-circuited image impedance and positive output impedance, is characterized by expressions for conversion gain, mixer noise figure, system noise figure, input and output impedance, and the signal source impedance required for minimum noise figure. The results of a typical numerical computation of these quantities are displayed graphically as a function of the local oscillator amplitude, with the bias fixed slightly below the peak voltage, in the positive conductance region. The experimental program has begun with tests of the i. f. portion of the mixer. (Author)
Investigation of photoconductor materials for a solid-state sonar display( Book )

2 editions published between 1964 and 1965 in English and held by 2 WorldCat member libraries worldwide

The purpose of this contract is to develop and construct a solid-state sonar display of variable persistence. The display device utilizes a layer of electroluminescent material to generate the output light and a control layer of photoconductive material which accepts an input illumination from a servo-driven wand. An opaque enamel layer between the other two layers is used to prevent optical coupling between the display output light or ambient illumination and the control photoconductor. Full-size display panels with the 50 range elements and 36 angular positions have been constructed. The photoconductor was sintered onto the panels in a specially designed two-zone furnace. Good brightness and brightness-decay uniformity have been achieved. Decay to one tenth of original brightness of 9 sec maximum and 250 ms minimum were obtained. The filter circuits of the Government-furnished equipment were tuned and the whole system performance was evaluated with an input generated by two types of simulators. One of the simulators was synchronous and generated an input which produced a fixed pattern on the display panel. A second simulator produced a constantly changing trace on the display. Both of these tests confirmed earlier predictions that the bandwidth of the filters did not permit a single element output on the panel. (Author)
Investigation of refractory compounds as thermionic emitters( Book )

1 edition published in 1962 in English and held by 1 WorldCat member library worldwide

Grain boundary cracking in metals under stress at elevated temperatures( Book )

1 edition published in 1961 in English and held by 1 WorldCat member library worldwide

A study was made of the effect of purification and of a number of metal and oxide additions upon the occurrence of intergranular cracking in brass, Cu, Ni, Ti and Zr under t nsion at elevated temperatur s. Purificatio by a variety of means inhibited in ergranular cracking in brass, Cu, and Ni. Zr additions also decreased the frequency of grain boundary cracks in brass and Cu, while Al2O3 additions increased the number of cracks. Under a wide variety of conditions, Ti and Zr of commercial purity were immune to grain boundary cracks and intergranular fracture. A few experiments re performed to demonstrate t e parallel effect of impurities and additions upon the nucleation of voids during diffusion; the initiation of grain boundary cracks during creep; the mechanism of crack nucleation by vacancy condensation is discussed (Aut or)

1 edition published in 1965 in English and held by 1 WorldCat member library worldwide

The investigation of chelate lasers has as its objective the evaluation of the potentialities of liquid lasers and the analysis and improvement of their performance. Toward this end, the work was designed to proceed along two parallel and complementary lines: an investigation of the chemical properties of the materials, in terms of the requirements for laser action; and an investigation of the physical properties of the chelate laser itself, in terms of the design and improvement of the laser cavity and associated equipment. The report summarizes previous work and describes in detail the progress on these lines in the past year. A full-length paper entitled 'Spectroscopy and coordination chemistry of europium chelate solutions: concentration and solvent effects' is included as an appendix

1 edition published in 1964 in English and held by 1 WorldCat member library worldwide

This report describes a project (1) to determine changes that occur in the composition of the gas during operation of a discharge tube such as is used in helium-neon lasers, and (2) to develop suitable instrumentation for such investigations. The omegatron mass spectrometer system that was developed is described, and data obtained with it on a helium-neon laser are reported. The laser output power and intensities of some lines of the emission spectrum of the discharge are also reported as functions of time of continuous operation of this laser. (Author)
Thin films formed by electrochemical reactions( Book )

1 edition published in 1962 in English and held by 1 WorldCat member library worldwide

The preparation of several hundred thin-film Ta capacitors confirmed previous findings that the type of glass and the cleaning procedure used were necessary for obtaining high-quality capacitors. With the preparation of a large number of capacitors, data have been obtained on the uniformity of capacitance values. Improvements in both uniformity and electrical characteristics resulted from a reduction of the substrate temperature during tantalum sputtering, from the treatment of the sputtering mask and from spectroscopic monitoring for impurities in the glow discharge. The evaluation of electrical properties was extended to cover a range of frequencies and temperatures. The preparation of thin-film resistors by anodization of sputtered and vacuumevaporated Ta was accomplished. Resistance was reproducible to within 0.3% of the desired value. The films were evaluated for power dissipation, and the temperature coefficient of resistance was determined as a function of sheet resistivity and film thickness. (Author)
A solid-state self-scanning display device. Prepared for: Rome Air Development Center, Air Force Systems Command, U.S. Air Force by M. S Wasserman( Book )

1 edition published in 1962 in English and held by 1 WorldCat member library worldwide

Materials are investigated for use in a solidstate electroluminescent display device in which the electric field for activation of the electroluminescent layer is provided by elastic waves propagated through a piezoelectric ceramic plate which serves as the substrate for the display. The work was subdivided into a search for piezoelectric ceramics with improved properties for use as the display substrate and the input transducers, the development of procedures for fabrication of thin large-area piezoelectric ceramic plates, and a search for materials for improved nonlinear resistor layers for the suppression of spurious light in the display. (Author)

1 edition published in 1964 in English and held by 1 WorldCat member library worldwide

A study of injection electroluminescence in p-n junctions was chosen as the most promising approach to the development of a high brightness, high-efficiency low-voltage dc injection electroluminescent light source for display device applications. The compounds GaP, AlAs, AlP, and solid solutions of them and with GaAs, were selected for study, based upon considerations of forbidden energy bandgap and a carrier mobility. Important results are the preparation of polycrystalline AlAs of relatively high purity and the use of this material to prepare single crystal epitaxial layers whose major constituent is AlAs. Epitaxial growth of AlAs layers requires temperatures above 1100C. These temperatures were obtained without introducing interference from competing reactions with the container by adapting a close-spacing procedure in which the source material and the substrate are separated by approximately 0.020 inch. This procedure also provides higher crystal growth rates than those obtained with conventional sealed-tube methods. (Author)
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English (48)