Probe set

Figure 15. Patterns of capabilities two selected individual or mixed pore column sets Probe Mix 3.

Figure l8. Patterns of capabilities Wo selected individual or mixed pore. column sets plus reference four column set Probe Mix 6. 

In this study, we only utilize one kind of probe-1 (P-1) DNA-conjugated polymer and easily set probe-2 (P-2) DNA on substrate, through hybridization between P-1 DNA and P-2 (Fig. 11) to analyze various target DNA, resulting in a DNA sensor that can analyze two different types of target DNA and distinguish fully matched from single nucleotide polymorphism (SNP) sequences. 

Another computational study at the Hartree-Fock level, using the 3-21G and 6-31G basis sets, probed the decomposition of di- i-Li2B2H4 into diborane(4) products containing 0,1, or 2 lithium atoms. The three reactions and the energies (relative to Li2B2H4 = 0.0 kcal/mol) are [6] ... 

Figure 3 Experimental set-up for bond inspeelion (a) and probe for the Fokker Bond Tester (b).

Interpretation of the impedance signal for set 2 (imaginary part function of the probe position along the slot)... 

The curve is symmetric from the middle of the slot. Hence the length of the defect is determined by the position of its edges at (x2+x3)/2 and -(x2+x3)/2 in the scanning direction of the probe. Of course this result is only true if we can distinguish the 5 zones on the curve. For other relative dimensions, for example a slot smaller than the probe (outer diameter), a curve like in set 1 is obtained, where the zones are confused. 

Modularity problems the instrument includes many different boards which are very well made for standard applications, but it is sometimes diffieult to set up a new type of examination. For example use of multiple probe, or multi-elements probes. 

The operation is quite simple One sets the frequency to the lowest value, adjusts the gain and phase to the desired sensitivity using a special calibration standard discussed below and performs a zero-compensation on a defect free zone of the standard. Now one is ready to test. As one slides the probe across the surface of an aluminum structure, a signal response will be indicative of the presence of corrosion or of the presence of a subsurface edge. 

The sensibility to defects and other testing parameters of pieces can be modified by the geometry of the piece to be controlled and the conception of the probe. It is sufficient to set the direction of circulation of eddy currents, regulate the magnetic field intensity and choose the coil of the appropriate size. 

This paper deals with the control of weld depth penetration for cylinders in gold-nickel alloy and tantalum. After introducing the experimental set-up and the samples description, the study and the optimization of the testing are presented for single-sided measurements either in a pulse-echo configuration or when the pump and the probe laser beams are shifted (influence of a thermal phenomenon), and for different kind of laser impact (a line or a circular spot). First, the ultrasonic system is used to detect and to size a flat bottom hole in an aluminium plate. Indeed, when the width of the hole is reduced, its shape is nearly similar to the one of a slot. Then, the optimization is accomplished for... 

Combined equipment" verification enables to check daily or on site the good working of flaw detector connected to probe. It is based on a set of simplified measurements. 

At the start of the development, it had been intended use an expert system shell to implement this tool, however, after careful consideration, it was concluded that this was not the optimum strategy. An examination procedure can be considered as consisting of two parts fixed documentary information and variable parameters. For the fixed documentary information, a hypertext-like browser can be incorporated to provide point-and-click navigation through the standard. For the variable parameters, such as probe scanning paths, the decisions involved are too complex to be easily specified in a set of rules. Therefore a software module was developed to perfonn calculations on 3D geometric models, created fi om templates scaled by the user. 

Templates for each of the joint configurations are stored within the system. The operator selects one of the templates, and is provided with a visual representation, as shown in Figure 3, on which he can alter the Joint dimensions and weld geometry to match those of the item to be examined any ae-cess restrictions can also be defined. Using information from a database of available probes, along with the examination level required, ProcGen then calculates the set of scans required (see Figure 4). 

Figure 5 shows the display in the measure mode. It consists of a detailed A-scan window and a number of smaller windows for display parameters and inspection parameters. The A-scan display may be used as a stand-alone tool or as a tool for measuring parameters required for a specific inspection, e.g. probe parameters, reference echoes, and depth compensation with automatic transfer to the data set. 

This paper intends to give, through different examples, guide-lines for characterization of array probes. We discuss, particularly, beam pattern measurement methods and raise the question whether it is useful to achieve a full characterization of all beams steered by the probe or to limit the characterization to a minimum set of acoustic configurations. An automatic bench for full characterization of tube inspection probes is described. 

For all the probes we design a specific and simple measurement set-up. The figure 2 illustrates the three different targets we made for the illustrated probes, following the rules ... 

And third, the set-up must lead to a reliable and reproducible positioning of the probe, as close as possible to the positioning of the probe on its industrial stage. 

Once the probe is set into the target, the acquisitions consist of the peak to peak amplitude, the time of flight and the frequency response of the back-reflected echo. 

Figure 3 Set-up for the dual array probe characterization a/ for angle beam measurements b/ for focused beam characterization...

The required acoustic verifications depend on what the probe is made for. If the probe is used as an angular scamiing system with a fix set of elements, then we think it is only needed to characterize the array behavior with a few selected time delay laws to isolate the angular steering capability and the foeusing capability as explained before. 

However, if the probe is used as linear scanning system, the acoustic beam depends on the element characteristics which are liable to change from one element to an other. Therefore, the only two alternative proposals are to characterise the aeoustie behaviour of all active sub-set of elements or to proeeed to a statistical characterization. 

Figure 4 Acoustic beam characterization set-up for the immersion SW array probe a/ Angle beam characterization principle b/ General view of the automatic bench...

To increase the sensitivity, direction of amplitude variation of probe output signal in defective area must coincide with the one after CCF processing. If the defect decreases the probe signal (single contact probe) A((/should be set Ai// = 0, in the opposite case (twin contact probe) it should be set Aif/= n. So the instrument should be supplied with a device to adjust A((/ and to sustain it constant. 

The Evaluation system is a Windows based open system through DLL, Dynamic Link Library, which provides great flexibility in evaluation and presentation of data. It also makes it possible to customise evaluation and images for special applications The time gates can be set after testing and there is a 256 colour range for amplitude. The software include FFT -facilities which enables measurements on used probes for parameters such as center frequenzy and bandwidth. 

Since it was required by LM Glasfiber that the scanner should be able to inspect joints between the shells and the iimer beams on each side and also the joints between the shells on the leading and trailing edge of the rotor blades, the X-Unit module was designed with three different set-ups for the Y-modules, which perform the movement of the probes transverse the length of the blade. The three different set-ups of the Y-modules are ... 

In set-up 2 the leading edge can be scanned by means of a special designed Y-module that allow the probe to follow the complex geometry of the leading edge from the root to the tip of the rotor blade. In figure 4 set-up 2 is illustrated. 

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