M-lines technique

The waveguides were optically characterized at X = 632.8 nm. The effective mode indices were determined by the m-line technique, based on a standard two prism coupling set-up. The refractive index depth profiles of the fabricated waveguides were reconstructed by the means of the inverse WKB procedure . 

Eq. (94) can be corrected for absorbing samples if the linear absorption coefficient is known. In any case, the value of the linear refractive index must be known. For liquid samples an Abe refractometer can be used. For solid samples index matching liquids can be used, although for thin films the most convenient method is the m-line technique [68]. 

In this paper we review the linear and nonlinear optical properties studies performed on solutions or thin film of rotaxanes and catenanes. Tlte linear optical properties were studied by U V-Vis spectrometry and m-line techniques. Tlte nonlinear optical properties were studied by second (SHG) and third (THG) harmonic generation in thin films and by electro-optic Kerr effect measurements in solutions. 

The refractive indices of vacuum deposited thin films of the studied catenanes and rotaxanes were determined by the m-lines technique. It consists on finding solutions of an eigen equation for modes propagating in thin film. For a planar waveguide. 

Figure 13. Schematic representation of experimental set-up for refractive index and thin film thickness determination by using the m-lines technique...

Procedure To the sample which contains 20-300 /xg of pertechnetate in 5-20 ml of solution, are added potassium perchlorate solution (2 ml, 1 mg KCIO per ml) and enough NaCl to make the solution approximately 1 M. The solution is heated and neutralized with ammonia. Pertechnetate is precipitated with aqueous 5 % tetraphenylarsonium chloride reagent. The precipitate is filtered, washed and dried, and a 2-mg portion is mixed with potassium bromide (300 mg). The mixture is pressed to form a clear disc by the usual technique. The infrared spectrum is recorded between 10 and 12 /x. The peak absorption is measured at 11.09 /X by the base-line technique. 

Nanospray is a miniaturized version of electrospray. In the original setup of Wilm and Mann (8) it is utilized as an off-line technique using disposable, finely drawn (1 -gm tip), metallized glass capillaries to infuse samples at 10-30 nL/min flow rates. This allows more than 50 min analysis time with just a 1-pT sample. Due to the formation of much smaller droplets and the more effective ionization, there is often no need for LC separation, since the separation is accomplished in m/z or by MS/MS. However, limited reproducibility with respect to quantification and a more complex sample preparation can be seen as drawbacks. An on-line version for hyphenation with capillary and nano-LC as well as CE (slightly modified) is now commercially available. 

Two types of Cr + luminescence centers have been found in steady-state natural alexandrite, characterized by J -lines at approximately 680 and 692 nm, accompanied by very many M-lines of Cr-Cr pairs (Tarashchan 1978). Those centers have been identified as connected with substitutions of AP" in different structural sites. It was found that natural alexandrites with very rare exceptions are characterized by very low CL intensities (Ponahlo 2000). Pulse CL study revealed that the spectrum consists of a relatively broad red band peaking at 685-695 nm, accompanied by narrow lines with the strongest one at 679 nm and the weaker ones at 650,655,664,700,707 and 716 nm. All lines and bands have been ascribed to several Cr + centers (Solomonov et al. 2002). The natural chrysoberyl and alexandrite in our study consisted of six samples. The laser-induced time-resolved technique enables us to detect two different Cr and possibly Mn + and V emission centers (Figs. 4.54-4.55). 

The synthetically useful dianions [M3(CO)u]2- were first isolated by Shore and co-workers as the Ca2+ (M=Ru) and the K+ (M=Os) salts by the reduction of M3(CO)12 using alkali metal benzophenone solutions in THF.1 [Ru3(CO) J2 reacts with Ru3(CO) 2 to form the higher nuclearity clusters [Ru4(CO)13]2- and [Ru6(CO)i8]2- but the triruthenium anion can be obtained in high purity by slowly adding triruthenium dodecacarbonyl to an excess of reducing solution using vacuum-line techniques.2 Vacuum-line syntheses of both dianions have been described in detail.1... 

Dilworth S, Mackin LA, Weir S, Clayboum M, Stott PW. In-line techniques for end-point determination in large scale high shear granulation. In I42nd British Pharmaceutical Conference. 2005. 

Mass spectrometry (MS) techniques are based on measurement of the charge/mass (m/z) ratio of molecules ionized by electron impact, laser irradiation, or by interaction with electric fields. Several MS methods have been applied in the study of grape and wine proteins initially as off-line techniques, then coupled to LC and CE techniques. 

Stock s designs for chemical vacuum line apparatus were widely disseminated. A leading American inorganic chemist, Professor L. M. Dennis at Cornell University became familiar with Stock s apparatus in the course of trips to Europe and he utilized chemical vacuum lines to investigate the hydrides of germanium in the late 1920 s(l). About this same time chemical vacuum line techniques were... 

After the initial studies of Gutowsky and Holm (1956) on the rotation barrier in amides about the C—N bond, Phillips (1958) completed a survey of several types of molecules amenable to the N.M.R. technique. The methyl groups in jViVT-dimethylformamide show distinct signals at room temperature and collapse to one line on raising the temperature. This is due to the internal rotation... 

Using standard Schlenk-line techniques, 200 mg of Rh2(02CCH3)4,-(MeOH)2 (0.395 mmol), 5 mL of a 1 M solution of (Et30) [BF4] in CH2CI2 (S.Ommol, Aldrich), and 10 mL of CH3CN (freshly distilled from calcium hydride) are refluxed in a 100-mL, three-necked, round-bottomed flask at... 

Farquhar, G. D., B. K. Henry J. M. Styles, 1997. A rapid on-line technique for determination of oxygen isotope composition of nitrogen-containing organic matter and water. Rapid Commun. Mass Spectrom. 11 1554-1560. 

Preparation of fl -dilithioferrocene-TMEDA [209] The whole procedure is carried out under an inert, dry atmosphere with freshly dried solvents stored under inert gas using standard Schlenk line techniques. n-Butyllithium (160 mL, 2.3 M) in -hexane), was added to 30 g (0.16 mol) of ferrocene (recrystallized from hexane), followed by 30 mL (0.20 mol) of N.N,N N -tetramethylethylenediamine (TMEDA, distilled from BaO under argon). The reaction was allowed to proceed overnight, ca. 16 h. The product was filtered off, washed with 3 x 100 mL of hexane, and dried imder vacuum. This gave 44.9 g (92% yield) of an orange pyrophoric powder, sensitive to moisture. The compound was recrystallized from THE at -40 °C. 

C-N.m.r. lines have been assigned to the terminal, central and directly attached monosaccharide residues in a triterpenoid saponin with a trisaccharide moiety, on the basis of decreasing spin-lattice relaxation times, the so-called "partially relaxed Fourier transform" method. The solution conformation of acarbose (16) has been determined by H and n.O.e. n.m.r. techniques and compared with that predicted by hard-sphere exo-anomerlc effect calculations. 

Figure 4.13 illustrates several techniques for patterning PEDOT PSS via electrochemical overoxidation. Conversion of a simple plotter pen or a screen-printing station are relatively straightforward, the latter allowing print resolution of a few hundred micrometers. To demonstrate that the technique is limited only by the resolution of the printing method, 2 p,m lines (the smallest mask available) were patterned in a 200 nm thick film with the aid of a photoresist mask [29]. 

The rate at which protons are exchanged in liquid ammonia has been measured by n.m.r. techniques . Three peaks appear in the proton magnetic resonance spectrum of pure liquid ammonia due to spin-spin coupling of the protons with the i N-nucleus. When a trace of ammonium salt is added the signal changes to a single line, which is attributed to... 

Sometimes, especially when it may be necessary to check the homogeneity of films in the volume close to the surface, it is useful to combine m-line spectroscopy with another method, such as an Abeles modified method (Hacskaylo, 1964). As these two techniques may provide complementary information, a more accnrate and detailed characterization may be achieved (Pelli, 2002). 

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