摘要:

An electrical discharge suppression system for a medium throughput (∼2  l/s) pumping line has been devised that works up to potentials of ±15 kV. This device permits atmospheric pressure ionization sources to be interfaced to high‐resolution, magnetic sector mass spectrometers with source potentials of 6–10 kV.

ISSN:0034-6748    

DOI:10.1063/1.1139855

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We present a small pump which is particularly useful when the conventional transfer method for pressurizing liquid nitrogen is unavailable. Its transfer rate ranges from 0.2 to 0.8 l/min depending on the speed of reciprocating motion of a piston driven by an electric motor.

ISSN:0034-6748    

DOI:10.1063/1.1139856

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Noncontact eddy‐current techniques for characterizing superconductors between 5 MHz and 1 GHz are described. Both a transmission and a frequency‐modulation technique rely on modification of the mutual inductance between a pair of coupled inductors. The sample is placed between the inductive sensors; the magnitude of eddy currents induced in the sample, a function of conductivity, modifies the mutual inductance. The frequency‐modulation method (where the sensors are the inductive section of a series‐resonantLCcircuit in an oscillator) is particularly useful for determining the critical temperature (Tc) and transition width for superconducting samples.

ISSN:0034-6748    

DOI:10.1063/1.1139857

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

We describe a useful method using a commercial linear variable differential transformer as a detector to characterize a piezoelectric ceramic tube as a displacer. Results show some inhomogeneity in the reduction of the voltage‐to‐displacement conversion of commercial piezoelectric tubes as a function of temperature from room to liquid‐helium temperature.

ISSN:0034-6748    

DOI:10.1063/1.1139804

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The photoluminescence decay of GaAs/AlGaAs quantum wells was successfully measured at room temperature by using 660‐nm picosecond light pulses from an AlGaInP diode laser driven by short pulse current. Our experimental results reveal that picosecond light pulses from visible diode lasers may be widely applicable, in place of mode‐locked gas, solid‐state, or dye lasers, for studying the fast carrier recombination properties of many kinds of materials including GaAs and AlGaAs in the wavelength region of deep red to infrared.

ISSN:0034-6748    

DOI:10.1063/1.1139805

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The rotor of a split‐pole asynchronous motor is used to circulate a dye solution in a cylindrical dye cell. A compact high flow dye cell which is suitable for high repetition rate (>100 Hz ) pumping has been thus developed.

ISSN:0034-6748    

DOI:10.1063/1.1139806

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A conversion of graphite into diamond was carried out by a new type of high‐pressure apparatus using thermal stress. In this apparatus, high pressures and high temperatures were simultaneously generated by heating a metallic ball embedded in a ceramic cylinder. It was confirmed by an x‐ray diffraction study that a part of the graphite sandwiched between the metallic ball and ceramic cylinder is transformed into diamond.

ISSN:0034-6748    

DOI:10.1063/1.1139807

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

A novel design for a biaxial goniometric stage is described. The two stacked mutually perpendicular arc sections of the conventional eucentric goniometer head are replaced by a single tilt platform. The principal feature is the motion of a spheroidal cap in a matching socket, permitting two‐dimensional tilting action about a fixed center of rotation. This design has the advantage of a significant decrease in overall height of the goniometer head, providing additional space for a variety of attachments.

ISSN:0034-6748    

DOI:10.1063/1.1139808

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The luminescence of tris(2, 2’‐bipyridyl)ruthenium(II)chloride [Ru(bipy)3Cl2] excited by picosecond‐laser pulses is introduced as an optical step signal for testing of the time response of optical detection systems in the time range of a few nanoseconds.

ISSN:0034-6748    

DOI:10.1063/1.1139809

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

The simple high‐pressure DTA cell that can be used for liquid samples was constructed. The advantage of this device is the facility of its operation. The utility was demonstrated by measuring the freezing temperature ofn‐tetradecane under various pressures up to 300 MPa.

ISSN:0034-6748    

DOI:10.1063/1.1139810

出版商:AIP    

年代:1988

数据来源: AIP