摘要:

A simple apparatus and special techniques are described which have been used to purify and to grow single crystals of KCl and KBr. The measured inpurity content of such crystals is lower than that of commonly used, commercially available crystals by a large factor. Residual impurities have fractional concentrations, in most cases, of less than ten parts per billion. The techniques used, with appropriate modifications, can be employed for the growth of most of the other alkali halides.

ISSN:0034-6748    

DOI:10.1063/1.1719687

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Considerations are discussed which underlie the choice of operating principles for mechanoelectric transduction in very high temperature environments. An experimental displacement pickup is described which uses a mutual‐inductance principle and functions well at 1100°C.

ISSN:0034-6748    

DOI:10.1063/1.1719688

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A simple apparatus for proton‐resonance magnetic‐field measurement permits remote location of the rf source and indicator. A high stability variable‐frequency oscillator is also described.

ISSN:0034-6748    

DOI:10.1063/1.1719689

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A method is described for measuring very small deviations from linearity in electric characteristics. The measurement is based on the harmonics generated by the nonlinear element when subjected to a sine wave signal. A special bridge circuit is used to balance out the undesired harmonics of the signal generator together with the first harmonic frequency. The set‐up measures the small‐signal value and the first and second derivative with respect to voltage. The detailed circuits are given for measuring nonlinearities in Ohmic and capacitive components. In the Ohmic case, a sensitivity in the measurement of the relative second order nonlinearity of about 5×10−8is obtained. In the capacitive case, the sensitivity expressed in terms of the minimum measurable values of the derivatives isdC/dV= 1.5×10−17F/V andd2C/dV2= 2×10−16F/V2.

ISSN:0034-6748    

DOI:10.1063/1.1719690

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A ``double‐clamshell'' arc image furnace system has been successfully utilized in a practical arrangement for the measurement of thermal expansion and electrical conductivity under a controlled atmosphere. Maximum sample temperature of 2138°K has been achieved by using two 5000 W xenon arc lamps as energy sources. At 1500°K, a temperature gradient of 6°K/cm was measured along the furnace axis by thermocouples shielded with alumina, but without a sample in position. The thermal conductivity of a sample would reduce the gradient to less than 1°K/cm.

ISSN:0034-6748    

DOI:10.1063/1.1719691

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A system design based on the use of a stored program on‐line computer is presented here. The system is used as an associative radiation analyzer. The channel capacity of the system is 20 bits (one million channel analyzer). The data storage program is based on a threaded list (tree) algorithm. The number of different events which will be measured during a particular experiment can be assigned for each experiment. The count capacity is 4096 counts per channel, but can be extended. Two alternatives are discussed, depending on whether a fast or medium speed computer is used. The mean input rates are 5000 or 1000 events per second alternatively. In both cases the resolution between two events is determined mainly by the analogue‐to‐digital converters used. There is a good flicker‐free display on the CRT. The display can be in map, isometric, or curve form. The display format (grid, unblanking, etc.) as well as the experimental conditions are under typewriter control.

ISSN:0034-6748    

DOI:10.1063/1.1719692

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A diaphragm pressure transducer has been developed for the purpose of separating a sample fluid from a hydraulic oil used in a dead weight tester. The diaphragm null position is determined by a commercially available magnetic sensing unit. The null position shifts systematically with absolute pressure, but the shift is reproducible and may be calibrated. With the output scheme utilized, the unit has a sensitivity of 0.00007 atm and a reproducibility of 0.0003 atm. The equipment has been used extensively at pressures up to 70 atm, but as designed should be operable to much higher pressures. The equipment described includes a small injector for refined pressure adjustments.

ISSN:0034-6748    

DOI:10.1063/1.1719693

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A cell for the measurement of dielectric parameters of hygroscopic materials over the frequency range from 0 to 100 Mc and at temperatures from −50 to 150°C is described. Provision is made for measurement of humidity inside the cell.

ISSN:0034-6748    

DOI:10.1063/1.1719694

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

An airborne microwave refractometer system was tested to determine its noise spectrum and the distribution of this noise within the system. Samples of atmospheric turbulence spectra are shown from about 180 to 1800 m above ground [about 1800 to 3300 m above msl (mean sea level)]. Total noise in a 0.03–15 cps passband is found to be about 0.04 ppm rms and to be approximately ``white.''

ISSN:0034-6748    

DOI:10.1063/1.1719695

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Apparatus and techniques are described for cleaving large (1 cm3) crystals of CdS and for making photoemission quantum yield and energy distribution measurements in the vacuum ultraviolet (hv≤ 11.8 eV; &lgr; ≥ 1050 Å) and at longer wavelengths. It is found that CdS cleaves only in the (101¯0) and (12¯10) planes. The cleaving and measurements are done at pressures of 10−9Torr or less, in a metal system provided with a VacIon and a titanium sublimation pump. For measurements in the vacuum ultraviolet, the sample chamber is provided with a LiF window and a special face plate which can be attached directly to the output housing of a vacuum monochromator. Measurements have been made forhv≤ 21.2 eV by mounting the cleaving chamber directly on the output housing of the vacuum monochromator, with no window between the sample and the vacuum monochromator. In this case the cleaving and measurements are carried out at the much higher pressure (10−4Torr or greater) of the vacuum monochromator.

ISSN:0034-6748    

DOI:10.1063/1.1719696

出版商:AIP    

年代:1965

数据来源: AIP