摘要:

Two‐step electrochemical etching is used to fabricate a palladium microprobe having a tip diameter less than 20 nm. The first etching is done at 4–7 V in a solution containing 4:6 volume ratio of HCl:HNO3, while in the second the etching, low voltage pulses are used.

ISSN:0034-6748    

DOI:10.1063/1.1144352

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

This reliable, high input impedance, unity gain metal‐oxide‐semiconductor field‐effect transistor preamplifier is an improved design for cryogenic applications. The high input impedance is well suited for applications involving capacitive transducers. This circuit is directly immersible in liquid helium and thereby reduces the noise and spurious pickup associated with remotely located preamplifiers. In addition, the circuit utilizes easily available commercial parts which will reduce cost and the need to order nonstandard components.

ISSN:0034-6748    

DOI:10.1063/1.1144353

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

An interface converting a cone flow into a rectangular flow is attached to a conventional nozzle with a circular orifice. This assembly can be heated to 300 °C, due to a metal‐to‐metal contact between an orifice and a plunger and to a Teflon‐insulated copper wire of an electromagnet. At the top of the interface, two razor blades are attached to convert the rectangular flow into a slit flow. The enhancement factor (long axis/short axis) is 6 in fluorescence measurements. The signal intensity obtained by the slit nozzle is four times larger than the best value obtained by the conventional circular nozzle.

ISSN:0034-6748    

DOI:10.1063/1.1144354

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

We describe an experimental demonstration of a novel technique for liquid refractometry. A channeled spectrum is produced from an optical beam generated by a diode laser operating below threshold by intercepting half of the beam with a liquid cell. The spectrum is analyzed using a grating and a linear CCD array and provides information on the refractive index of the liquid. The experimental results show that accuracies of better than 0.3% in the index may be obtained with the present method.

ISSN:0034-6748    

DOI:10.1063/1.1144355

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

With a spring‐loaded platform mounted on a precision minidrilling machine, it is possible to rapidly and inexpensively drill sharp sample holes down to about 100 &mgr;m in hardened metal gaskets for diamond anvil cell experiments.

ISSN:0034-6748    

DOI:10.1063/1.1144356

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

A new gas expansion method is described to determine dead‐space volumes having a temperature contrast boundary. The observed volumes obtained agreed with those obtained from the conventional gas expansion method and the water filling method.

ISSN:0034-6748    

DOI:10.1063/1.1144357

出版商:AIP    

年代:1993

数据来源: AIP

摘要:

A miniature remote alignment and control system based on systems that are used in radio‐controlled models is described. The modified servos provide high output torque and proportional speed control for positioning alignment adjustments, spectrometer controls, accessories, or specimen stages.

ISSN:0034-6748    

DOI:10.1063/1.1144358

出版商:AIP    

年代:1993

数据来源: AIP