Alignment material cleaning

The instrument operated successfully for a period of over six months (from July to December 2005) with no user intervention for alignment or cleaning of any internal optical components. The only maintenance that occurred during this period was brushing material buildup from the ends of the probes during furnace maintenance shutdowns. This procedure required five minutes of effort. The maximum allowable time between cleanings was not determined however, the system was operated successfully for periods of up to four weeks without cleaning. 

The rubbing machine is covered with a hood, and an exhaust fan is used to prevent the diffusion of the dust from the rubbing cloth and alignment material. After the rubbing process, a cleaning process is used to wash away particles of the rubbing cloth and alignment material from the surface of the substrate. 

Since bits of the rubbing cloth and pieces of alignment material are embedded on the substrate by the rubbing process, a cleaning step is required after rubbing. The substrates are cleaned by using a normal process with purified water and ultrasonic vibration, and then dried. 

From unwind to rewind rolls, there are a number of rolls over which uncoated and coated substrates travel. They are necessary to guide the web at an accurate position through the line. The rolls are running in ball or other type bearings that are precision ground. They must be kept clean and accurately fitted into the line on sturdy frames. They are kept in a perfect alignment in the line. When the substrate is a very light or a smooth material, it is frequently necessary for several of the rolls to be driven. For paper however, most auxiliary rolls are idlers. 

Figures 4.30(c) and 4.31(c) show HREM images representative of the catalysts reduced at 1173 K and further oxidised in pure O2 at 1173 K. The structure of both catalysts is clearly different from that observed after re-oxidation at 773 K. Notice that in this case both materials seem to be formed by small, crystalline, metal particles dispersed over the ceria surface. Fringe analysis confirms that these crystallites consist of metallic rhodium and platinum, respectively. Thus, the DDPs of the larger particles observed in the image of the Pt catalyst show 0.8 nm Moire-type fringes aligned with the (111 )-Ce02 reflections. These spots arise from double diffraction in the (lll)-Pt and (Ill)-Ce02 planes under a parallel orientation relationship. Therefore this result, in addition to confirm the presence of metallic Pt particles in the sample oxidised at 1173 K, suggest that these particles are epitaxially grown on the support. A detailed inspection also reveals that the exposed surfaces of these particles are clean, i.e. free from support overlayers.

Upon completion of the desired reaction the flame-sealed NMR tube is placed in the apparatus shown in Figure 2. The NMR tube must be scored and the score aligned with the stopcock A to insure a clean break of the tube (See Figure 2). The setup is then evacuated on a vacuum line while the contents of the NMR tube are cooled with liquid nitrogen (the tube is cooled to prevent rapid escape of the volatile materials upon exposure to the vacuum). Once evacuation of the apparatus is complete, stopcock B is closed and the sealed NMR tube is cracked by turning... 

The best method to obtain tentative identification of a substance is to spot the sample and reference compounds on the same chromatogram. Mobilities of all compounds are then compared under the same conditions, and a match in / p values between a sample and standard is evidence for the identity of the sample. Ideally, experimental conditions should be chosen so that the compound to be identified moves to a point near the center of the layer (approximate / p of 0.5). If / p values are higher than desired, the polarity of the mobile phase can be reduced for lower R p values, the polar component of the mobile phase can be increased. If the spots of interest from the sample do not align with any standards, they are either not the same as any of these compounds or their mobilities have been affected by extraneous material from the sample. If the latter is the case, sample clean-up may be necessary. Identification of a compound based on mobility in one chromatographic system is only tentative and should be confirmed by other evidences. It is common to chromatograph the sample and standards in several thin-layer systems to compare their mobilities, but this provides useful corroborative evidence only if the systems are truly independent [66]. 

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