Interferograms from a dual-comb spectrometer are continuously corrected and averaged in real-time. The algorithm is implemented on a field-programmable gate array (FPGA) development board. The chosen approach and the algorithm are described. Measurements with high signal-to-noise ratio, resolution and bandwidth are shown to demonstrate the accuracy of the optical referencing and the processing algorithm with 24 hours of averaging time, reaching a signal to noise ratio of 10,750,000 (>21 bits) in the interferogram and 316,000 in the spectrum at 100 MHz resolution. An interferogram where signal dominates the noise over the full delay range imposed by the 100 MHz repetition rate is reported for the first time.

Silica microspheres are probed with a dual comb interferometry setup. The impulse responses of these microresonators are measured with a temporal resolution smaller than 400 fs over more than 200 ps. The amplitudes and phases of the impulse responses are interpreted as providing sensing information. The more familiar transmission spectra corresponding to the measured impulse responses are also calculated and shown. Sensing is demonstrated by varying the concentration of isopropanol in de-ionized water surrounding the microsphere and by binding bovine serum albumin on the silanized microsphere surface.

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The reaction between nickel and potassium dithio-oxalate has been developed into a simple, quick, and precise method for the spectrophotometric determination of traces of nickel and has been applied to the analysis of this element in our studies on its electrodeposition on thin metallized plastic a m s . On making absorption measurements of the colored compound formed by the reaction in various bases and acids at different concentrations, it was found that a dilute sulfuric acid solution is a good medium for preparation of samples and making the measurements. Maximum absorption of the compounds occurs at 500 mp and obeys the Beer-Lambert law over a suitable range. The effect of various ions on the determination of nickel by the method has been measured along with the absorption curves of the compounds formed by the reaction of potassium dithio-oxalate with cobalt and copper. The relative merits of the method are discussed with reference to other methods of analysis of traces of nickel.Une methode spectrophotomktrique d'analyse de traces de nickel, baske sur la reaction de cet dement avec le dithio-oxalate de potassium, a kt6 mise au point. Au cours d'essais avec differents acides et bases, il a kt6 trouvk que dans une solution diluQ d'acide sulfurique le compose color6 issu de cette rkaction se forme rapidement et posshde la stabilitk requise pour faire des mesures d'absorption. L'absorption est maximale A 500 m p et obeit A la loi de Beer-Larnbert. En plus de mesurer les spectres d'absorption des composks formks par la reaction du dithio-oxalate de nickel avec le cobalt et le cuivre, nous avons dktermine les concentrations tolkrables pour plusieurs autres klkments qui contribuent A l'absorption A 500 mp. Cette mkthode a kt6 utilisk avec succbs pour I'analyse de nickel dans plus de quarante khantilIons, obtenus au cows d'ktudes sur l'klectrodkposition de cet klkment sur des films plastiques minces. La mkthode se caracthise par sa simplicitk et prksente plusieurs avantages sur celles dkjA dkrites pour l'analyse de traces de nickel.Canadian Journal of Chemistry, 46,1233Chemistry, 46, (1968 IntroductionThe reaction of nickel with potassium dithiooxalate, K2C202S2, first observed by Jones and Tasker (1) has been used by Fairhall (2) and Yoe and Wirsing (3) for the colorimetric determination of nickel. These investigations indicated that the reagent is extremely sensitive and permits the determination of very small amounts of nickel. The reaction has been further studied in order to establish if it could be developed into a simple, quick, and precise method for the spectrophotometric determination of microgram amounts of nickel in our work on the electrodeposition of the element on thin metallized plastic films (4). Thus, the absorption spectrum of the complex, the application of the BeerLambert law, and the effect of various ions and different experimental conditions have been determined. These studies showed that the reaction meets the requirements set above for our specific application and could also be applicab...

A study was made of the conductivity of thin flexible collodion films metallized either with gold (99.95%) or with gold -18% palladium alloy and the results obtained were compared with the conductivity of VYNS (a polyvinylchloride-acetate copolymer) films coated with the same metals. For both types of films the conductivity is better with the alloy, especially for VYNS. VYNS films coated with gold or the alloy show better conductivity than collodion coated with either metal. However, ionic bombardment of the collodion films prior t o metal coating considerably improves their conductivity, especially with the Au -1870 Pd alloy. For thid alloy the conductivity goes up by a factor of 100 t o 1 000 000, and then becomes better than that obtained with VYNS. Although ionic bombardment had a less pronounced effect on the VYNS, a n improvement in conductivity mas still observed.On a fait une Ctude comparative de la conductivitC de films minces de collodion e t de VYNS mCtallisCs soit avec de l'or, soit avec un alliage or -18Yo palladium, en couches variant de 2 & 30 pg/cm2. Pour les deux types de films, la conductivitC s'est rCvClCe meilleure avec l'alliage; de plus le VYNS devient plus facilement conducteur que le collodion. Toutefois, les films de collodion soumis & un bombardement ionique avant leur mCtallisation sont beaucoup plus faciles & rendre conducteurs e t leur conductivitC devient m$me supbrieure B celle obtenue avec les films de VYNS mCtallis6s par l'alliage. Quoique le bombardement ionique ait un effet moins prononce sur la conductivitC subsequente des films de VYNS, elle est tout d e meme amCliorCe de fason apprCciable. On dCcrit Cgalement des methodes simples e t rapides pour dCterminer I'Cpaisseur des films de collodion e t des couches mCtalliques dCposCes sur les films.