Sharpened probe

SPM Scanning probe microscopy (a general term encompassing all types of microscopy which utilize a scanned micro-sharpened probe and feedback circuitry to image nanometric phenomena, including AFM, ECAFM, LFM, STM, and many others)... 

STM probes (e.g., from W or Pt-It wire) are fabricated by either mechanical cutting or electrochemical etching. Further treatments are sometimes used to sharpen them, such as annealing under high fields 133434 in techniques handed down from the original atomic resolution microscopies—field emission microscopy and field ion microscopy.135 136 Another method employed is to lift an atom or molecule onto the probe tip so as to define the tip precisely. One important issue that can prevent clear interpretation of STM images but can also be used to tremendous advantage is the fact that the atom at the very apex of the STM probe... 

The Scanning Tunneling Microscope. An STM uses a sharp metallic tip as a probe for the measurement. The tunneling tip is typically a wire that has been sharpened by chemical etching or mechanical grinding. W, Pt/Ir, or pure Ir are often used as the tip material. A schematic view of an STM is shown in Fig. 2. 

The main problem in IR measurements in situ is a strong IR absorption by the solvent water. Therefore the measurements in the classical transmission mode are practically excluded (the path length must not exceed 15 tan). Short path lengths are provided by the attenuated total reflection (ATR) mode. The probing light beam undergoes multiple total internal reflection in the ATR element (e.g. a cylindrical rod made of ZnSe, with two cone-sharpened ends) and each reflection... 

The new measure has not only sharpened the tools for probing the surroundings around a single molecule, but it could also be applied to a vastly larger range of systems not only a single A in pure B, or a single B in pure A,... 

In a different application, Williams and coworkers were interested in using the SECM to identify a precursor state to the pitting corrosion of stainless steel (12) and also to elucidate the mechanism by which a pit could be maintained and propagate further (13), once it had been initiated. For these studies, a commercial AFM (Quesant Resolver ) was adapted for use as an SECM. The tip electrode was a Pt-Ir wire electrolytically sharpened and insulated, as for electrochemical STM. A two-electrode mode was used with a Pt counterelectrode of much larger area than the stainless steel working electrode. The potential of the counterelectrode was standardized against an SCE. The probe UME was maintained at the same potential as the Pt counterelectrode. Typical tip-substrate separations of 0.1-0.5 /xm were employed for imaging purposes, with the distance carefully established by ap-... 

One way of probing the fluctuations in rate constants is to sharpen the definition of the event. This is obvious on rather general grounds but the typical pump probe experiment... 

Some of the samples were annealed at 650 °C for one horn. The microscopic measurements were performed in a combined SEM/STM system based on a Leica 440 SEM operating under a vacuum of 1 x 10 Ton. The small size of the STM enabled it to be mounted on the SEM specimen holder. Mechanically sharpened Pt-Ir wires were used as probe tips for tunneling experiments. The STM was used in the conventional constant-current mode, in the current imaging tuimeling mode (CITS) and in the STM - REBIC mode. For STM-REBIC mode, two ohmic contacts were provided by small Hgin dots on the sample surface connected to Au or Pt-Ir wires. The tuimel tip was located on the region between the contacts and the current was measured at room temperature with a Keithley 428 current amplifier. 

When she reaches puberty, Harriet immediately claims the attention of the master of the household. Dr. Flint, now well into his fifties and portrayed by Harriet as a sly and volatile obsessive. He probes her reactions for an opening and follows patterns that would today identify him as a classic batterer.. .. But Jacobs s hatred sharpened her pen she captures Flint in exquisite detail. If you look at her portrait closely, the image of a monster slowly... 

---