摘要:

An electrical resistance counter of the Coulter type has been designed to count particles intended for animal injections and to dispense them into a package (a length of polyethylene medical tubing). The packaged particles are used for injections at a later date. In a typical application, two thousand 10 &mgr; spheres can be counted and loaded into a 61 cm length of PE‐50 tubing (total volume 0.25 ml) in about 5 sec. The accuracy of the count has been determined by an independent method.

ISSN:0034-6748    

DOI:10.1063/1.1684900

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

The characteristics of a transversely excited atmospheric pressure (TEA) CO2laser with a new electrode arrangement have been investigated. The electrode arrangement consists of two brass bars as anode and cathode with two flat side electrodes held at the same potential as the anode. The laser output is compared to that obtained from a conventional TEA laser in which the cathode consists of a row of resistors.

ISSN:0034-6748    

DOI:10.1063/1.1684901

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Space focusing of polar diatomic molecules using an electrostatic hexapole field is discussed, and it is shown that focused molecular trajectories in this type of field are properly described by a Jacobian elliptic function. Although a detailed mathematical treatment is given, emphasis is placed upon the physical nature of the trajectories. These results are applied to the design of a molecular beam resonance apparatus using hexapole fields, and it is shown that, in practice, several simplifying approximations (with little loss in accuracy) may be made which allow design calculations to be carried out using only a slide rule.

ISSN:0034-6748    

DOI:10.1063/1.1684902

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Two capacitive transducer designs have been used in this laboratory for amplitude measurements of longitudinal ultrasonic waves in solids. The designs are simple, can be fabricated easily, are rugged, and should prove to be a useful ultrasonic laboratory item. Each of the microphones can be conveniently altered to be used with a variety of specimen sizes, and displacement amplitudes as small as 10−14m have been measured for 30 MHz frequency longitudinal waves. As an example application of the transducer, measurement of phase shift upon reflection from an X‐cut quartz transducer bonded to an SrTiO3crystal is given.

ISSN:0034-6748    

DOI:10.1063/1.1684903

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

In many photoemission experiments the retarding voltage between the emitter and the collector is modulated to obtain an electron energy distribution curve. A technique is described in which the incident light beam is modulated as well, but at a much higher frequency. Problems arising from electronic and lamp noise and from stray shunt capacitance are reduced. If the light is modulated by varying its polarization, as in an experiment to study ``surface'' photoemission, the effects of reverse photoemission can also be reduced.

ISSN:0034-6748    

DOI:10.1063/1.1684904

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

Properties of plasmas produced by a 1.5 cm diam coaxial gun are investigated. Gas is provided from the center electrode material which is interchangeable. Materials such as lithium, titanium with occluded hydrogen, and carbon are used as the plasma source. Typically, a lithium plasma is produced which has equal ion and electron energies of 25 eV and 1017−1018particles/pulse.

ISSN:0034-6748    

DOI:10.1063/1.1684905

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

A combination magnetic densimeter and viscometer, which essentially simultaneously measures the density and viscosity on 0.3 ml specimens of fluids, is described. A small cylindrical buoy is freely suspended magnetically and coaxially with a larger surrounding cylindrical glass tube which contains the fluid in which the buoy is completely immersed. After calibration, the electrical current in the air core solenoids which magnetically support the buoy measures the density of the fluid while the period of revolution at constant power input determines the viscosity. The density can be measured to the order of magnitude of one part in 106and the viscosity to one part in 104.

ISSN:0034-6748    

DOI:10.1063/1.1684906

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

To avoid the time consuming process of high vacuum bakeout of laser tubes, we have constructed a variety of lasers which utilize a small mechanical forepump and a slow flow of the gas medium through the laser tube. No stringent requirements are placed on the vacuum integrity of the system; the gas flow rate (2–20 scm3/min) is sufficiently low that the use of commercially available tank gas is economically justifiable. The chief advantage offered by the flowing system is that laser operation can be obtained within minutes after exposure to the atmosphere; thus, the operator has access to a wide variety of operating pressures, gas mixtures, etc. A helium‐neon laser at 6328 Å and 1.15 &mgr;, helium‐cadmium at 4416 Å, and helium at 95 &mgr; have been successfully operated in this manner. The ease of operation in these three cases suggests that a wide variety of gas lasers can be constructed in this manner.

ISSN:0034-6748    

DOI:10.1063/1.1684907

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

In order to determine whether the thick thermal boundary layers in liquid metals lead to reduced directional sensitivity of hot film sensors, steady state calibrations for speed and directional sensitivity of cylindrical hot film sensors having aspect ratios of about 19 were made in a liquid metal by towing them through a long pool of mercury. The directional sensitivity is characterized by an empirical parameter,k, which varies from zero to one as the sensitivity varies from its maximum to zero. The results show that for measurements of flow direction, the sensor aspect ratio must exceed 20 for sensor Peclet numbers less than about 0.35. Thekare only weakly dependent on angle of inclination in the range 30–60°, a result which can be used to reduce the labor of calibration.

ISSN:0034-6748    

DOI:10.1063/1.1684908

出版商:AIP    

年代:1971

数据来源: AIP

摘要:

A method is described for producing pyrolytic carbon with efficiencies suitable for use with highly enriched isotopes. Dense cylinders 14 cm long×1.4 cm in diameter have been produced with 97% efficiency by the pyrolysis of13CH4. A process for converting13CO into13CH4is also described briefly. Some applications for nuclear spectroscopy are discussed.

ISSN:0034-6748    

DOI:10.1063/1.1684909

出版商:AIP    

年代:1971

数据来源: AIP