摘要:

A low‐cost technique is discussed for fabricating bridges down to 0.12&mgr; in width in aluminum using a conventional scanning electron microscope without a beam‐blanking facility. A detailed discussion is also given of the bridge pattern generators for the rectangular and Anderson‐Dayem geometries. The successful use of Shipley AZ‐1350 as an electron resist is reported.

ISSN:0034-6748    

DOI:10.1063/1.1686623

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We describe a cryostat for neutron diffraction experiments under pressure of 40 kilobar at 4.2–300 K. In this device liquid nitrogen is not used to cool the thermal screens. The pressure is transmitted by columns cooled only by helium boil‐off vapor. One of them can move freely over a range of several centimeters. The liquid helium consumption at 4.2 K is 0.7 liter/h.

ISSN:0034-6748    

DOI:10.1063/1.1686624

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

This paper discusses the construction of a cylinder flow reactor used for studying heterogeneous reactions, with particular reference to reactions involving NOx. This system incorporates methods of gas analysis such as optical absorption (NO2), chemiluminescent (NO or O3), gas chromatography (N2or O2) and mass spectrometry (SO2, etc). The system was constructed such that experimental conditions could be varied over a large pressure range from 1 to 700 Torr with a relative humidity variation of 0–90%.

ISSN:0034-6748    

DOI:10.1063/1.1686625

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Circuitry is described for the detection of turbulence. Also the criteria on which the detection is based are discussed. The device was used to study the features of the interface that exists on unbounded turbulent flows.

ISSN:0034-6748    

DOI:10.1063/1.1686626

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A circuit for measuring the energy in randomly occurring bursts of rf energy is described. The circuit is linear to within 10% (over a 15 dB dynamic range) for frequencies up to 1.5 MHz. Examples are given of its use with acoustic emission data from a martensitic phase transition in the indium thallium system and from a nondestructive test on a filament wound vessel.

ISSN:0034-6748    

DOI:10.1063/1.1686627

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A continuous wave ultrasonic instrument capable of measuring very small changes in acoustic attenuation and phase velocity is described. This transmission oscillator ultrasonic spectrometer (TOUS) exhibits high sensitivity because it oscillates marginally. In spite of this high sensitivity, the TOUS system is relatively simple, compact, and inexpensive. These features suggest that the TOUS is suitable not only for precise laboratory measurements of the physical properties of materials, but also for field applications in nondestructive testing.

ISSN:0034-6748    

DOI:10.1063/1.1686628

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

The current and the phase angle of the internal beam with respect to the accelerating voltage of the Eindhoven University of Technology AVF cyclotron are measured using a number of electrostatic induction pick‐up probes. Data handling is by means of sampling, correlating, and a CAMAC system. On the hf signal is superimposed a very strong first (fundamental) harmonic signal induced by the accelerating voltage. Therefore, the second harmonic component of the probe signal is used. Furthermore, all odd harmonic components of the signal are suppressed by using a special sampling technique. For the first harmonic component the suppression is about 60 dB.

ISSN:0034-6748    

DOI:10.1063/1.1686629

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A multipoint correlation technique is described for the measurement of the fluorescence decay from a sample excited with modulated light, where the modulation and the response can be arbitrarily complex. In the case of weak fluorescence, individual photons are resolved which are so correlated. The apparatus has a high dynamic range at extremely low photon densities, or very high photon rates, only limited by the single pulse resolution time of fast photomultipliers and counters.

ISSN:0034-6748    

DOI:10.1063/1.1686630

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A calibration for directional sensitivity of a conical hot film anemometer probe is described. It is usually assumed that the conical probe is insensitive to the velocity vector direction but, in fact, this is not so because deviations of ±60% of the mean velocity can occur at low water speeds. In this study, the probe is aligned at right angles to the velocity vector but the trend of the results applies to probes aligned along the velocity vector. An application of the conical probe to velocity measurements in a vortical water flow for speeds from 0.06 to 3 m/sec is discussed.

ISSN:0034-6748    

DOI:10.1063/1.1686631

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A flexible, powerful, and interactive computer‐assisted measurement system is described, based on a 16‐bit minicomputer and an extensive set of peripherals. A general purpose hardware‐software configuration is described which enables different users to computerize measurements in completely unrelated experiments, with minimal changes in interfacing. General purpose subroutines to control the digitizing of measurements are FORTRAN ‐callable from user programs. The result is a system for computer‐assisted measurements which may be used as a general purpose laboratory instrument, requiring only a knowledge of FORTRAN. Illustrative applications are described in several fields of physics. A comparative evaluation of other computerization schemes is given.

ISSN:0034-6748    

DOI:10.1063/1.1686632

出版商:AIP    

年代:1974

数据来源: AIP