摘要:

A clipped correlator made with two cascaded commercial chips is described. The correlator works in real time, has a very low cost as compared with the commercially available models, and is designed for velocity measurement in an industrial field. An example of application in the textile industry for measurements of fibers flow is presented. An accurate system for velocity measurement has been developed, calibrated, and tested. The cross correlation formed between the signals from the two photodiodes has a peak at a lag value corresponding to the passage time of samples from the first to the second beam.

ISSN:0034-6748    

DOI:10.1063/1.1139614

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

It has been shown that a virulent phageQ&bgr; can be cultured continuously in a cellstat which was developed to culture a bacteriophagefdfor the study of molecular evolution. A cloned disadvantageous mutant was cultured to obtain a biological relaxation curve to selection/mutation equilibrium. A new technique for scraping off the wall growth by air bubbles is introduced. The scraper worked well in short‐time cultivation ofQ&bgr;. It has various advantages of a closed system.

ISSN:0034-6748    

DOI:10.1063/1.1139615

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A simple evaporation gun for preparing organic thin films was fabricated using commercially available parts of an electron gun for a TV Braun tube. The device permits sample heating to be easily controlled because of the small heat capacity.

ISSN:0034-6748    

DOI:10.1063/1.1139616

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Thick‐film resistors, when used as thermometers below 1 K, have a heat capacity similar to that found in Matsushita carbon‐composition resistors.

ISSN:0034-6748    

DOI:10.1063/1.1139617

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Two innovations have been applied to improve a method developed earlier for the production of field‐ion tips. The new technique produces sharper, smaller tips with low‐aspect ratio shanks to fulfill the specific needs of scanning tunneling microscopy.

ISSN:0034-6748    

DOI:10.1063/1.1139618

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The gas‐handling system of a simple, inexpensive gas chromatograph is described suitable for the safe and fast purity analysis of tritium gas.

ISSN:0034-6748    

DOI:10.1063/1.1139619

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We present a design for a piezoelectric transducer holder for use at low temperatures, which is easily constructed and assembled. Improved acoustic signals with ‘‘ringing’’ eliminated were reliably obtained. The standard problems of demountability, electrical integrity, and leak tightness in the presence of liquid helium at moderate pressures were resolved.

ISSN:0034-6748    

DOI:10.1063/1.1139620

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We describe a sample mounting facility capable of cooling a graphite crystal to temperatures of around 10 K (to enable investigation of low‐temperature physisorbed phases) and which at the same time permits the crystal to be heated to 1300 K for surface cleaning. A demountable resistive heating mechanism avoids the conductive loading of the sample which normally inhibits the attainment of very low temperatures.

ISSN:0034-6748    

DOI:10.1063/1.1139621

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Nonresonant capacitive electrodes are shown to be convenient and effective for observing dielectric resonances in the microwave region where the sample size is small compared to the wavelength of the excitation. An example of rotational spectroscopy in a seeded supersonic expansion from a pulsed nozzle is presented.

ISSN:0034-6748    

DOI:10.1063/1.1139622

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A high‐pressure cell with sapphires as Bridgman anvils and a simple flow tube cryostat for optical spectroscopy are described. Temperatures down to 10 K and pressures up to 50 kbar are easily obtained.

ISSN:0034-6748    

DOI:10.1063/1.1139568

出版商:AIP    

年代:1987

数据来源: AIP