Needle-contact probe

Needle contact probes These are probably the simplest and least expensive devices. A needle is mounted on a micrometer and insulated from ground, except for the tip, by a nonconducting varnish. The needle is moved into the wavy liquid film flows along a conducting plate, which is grounded. As the needle is moved, the fraction of time during which contact with the liquid top takes place is noted, and is related to the probability that the film thickness is greater than some value. This technique can provide information on the minimum, maximum, and mean thickness with reasonable reliability. 

A useful tool is a pyrometer with a surface contact probe and a melt probe (needle probe). The contact probe can be used to check for heater burnout, barrel temperatures, die temperatures, and temperature distribution and variation. The melt probe can be used to check melt thermocouple accuracy and to measure the actual melt temperature as it exits the die. The melt temperature at the die exit can be higher than the melt probe temperature at the end of the extruder barrel. 

Figure 8 High throughput organic synthesizer developed in collaboration with Cyberlab, Inc. [25] and designed to process the 96-deepwell reaction blocks. The instrument is capable of tolerating a wide range of chemistry (liquid contacts are glass, stainless steel, or Teflon) and accomplishes the transfer of reagents with coaxial tip (N2 inlets) single-needle and four-needle probes.

From the fabrication of the capacitor we run into the problem of contacting the capacitor, which can mostly be done in two ways. The easiest way is to contact by standard metal needle probes on a probe station, however, this requires large contact areas larger than 3x3 nm2. But this also requires fully structured top and bottom electrodes as in Figure 17.6, or integrated devices, which are much more difficult to manufacture, especially for sub-micron capacitors. 

Electrochemical functionalization - reductive coupling of diazonium salts The electrochemical functionalization of SWCNTs, deposited on an Si/Si02 substrate, with 4-nitrophenyl groups succeeded by the reduction of 4-nitrobenzene-diazonium salt in a mini-electrochemical cell with platinum counter and (pseu-do-)reference electrodes. A probe needle was used to make contact with one of the Au-Pd bonding pads on the substrate and allowed the application of an electric potential to the electrode (-1.3 V vs. Pt for >30 s) and to any SWCNTs underneath the electrode [177b]. 

An important technique in studying the mechanism of fully developed boiling is to use electrical conductance probes that can be traversed from the bulk fluid to the surface. A tiny needle tip (typically less than 50 pm in diameter) will record the local presence of liquid or vapor, and the fraction of time spent in contact with the vapor gives the void fraction, typical of the measurements of this type are those of Shoji [100], illustrated in Figs. 15.49 and 15.50. 

The needle-type fom-point probe method may be more convenient to use to measure the conductivity of a plate because the solid plate will not be penetrated by the needles and the needles can achieve good contact with the plate. 

In the clinical environment, optical techniques have been used for decades (microscope, colposcope, ophthalmoscope, endoscope, laparascope). Integration of spectroscopic devices into existing procedures is an obvious task. Fibre optic cables provide a flexible solution for adequate optical interfacing between the optical and spectroscopic device and the sample to be interrogated in situ. Fibre optic probes can be inserted into cavities and tubular structures, put in contact with epithelial surfaces and also inserted into structures that can be punctuated by rigid devices such as needles. Fibre optic devices for optical spectroscopy can be manufactured as flexible catheters with an outer diameter not exceeding 0.5 mm. We will present in this article fibre optic solutions for... 

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