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1.
High power industrial multibeam CO2 lasers consist of a large number of closely packed parallel glass discharge tubes sharing a common plane parallel resonator.
Every discharge tube forms an independent resonator. When discharge tubes of smaller diameter are used and the Fresnel numberN ≪ 1 for all resonators, they operate in waveguide mode. Waveguide modes have excellent discrimination of higher order modes.
A DC excited waveguide multibeam CO2 laser is reported having six glass discharge tubes. Simultaneous excitation of DC discharge in all sections is achieved by
producing pre-ionization using an auxiliary high frequency pulsed discharge along with its other advantages. Maximum 170 W
output power is obtained with all beams operating in EH11 waveguide mode. The specific power of 28 W/m is much higher as compared to similar AC excited waveguide multibeam CO2 lasers. Theoretical analysis shows that all resonators of this laser will support only EH11 mode. This laser is successfully used for woodcutting 相似文献
2.
G. S. Deshmukh 《Fresenius' Journal of Analytical Chemistry》1955,145(4):251-253
Summary The quantitative oxidation of thiocyanate by ceric sulphate has been studied and the method utilised for the determination of small quantities of cerium by back titrating the excess (unreacted) KSCN against standard mercuric nitrate with diphenylcarbazone as the internal indicator. Accurate results are obtained under the specified experimental conditions and the procedure is more simple and direct than that adopted during earlier studies of the above redox reaction.Grateful thanks of the author are due to Professor S. S. Joshi for facilities during the work and to the National Institute of Sciences of India for award of a Research Fellowship. 相似文献
3.
V. D. Anand J. P. Srivastava G. S. Deshmukh 《Fresenius' Journal of Analytical Chemistry》1962,191(5):321-329
Summary The polarographic behaviour of nickel and cobalt in the mixed base electrolytes, urea-pyridine and urea-hydrazine has been studied. The effect of pH, concentration of supporting electrolyte and the presence of various other ions was investigated. Well defined polarograms for both the elements were obtained at pH 6.0 and 5.0 respectively. Attempts were made to utilize these observations in the separation of the two cations. While the difference in E
1/2 of the ions in urea-pyridine was greater than –0.3 volts that in urea-hydrazine was about –0.2 volts or slightly less even under the optimum conditions. In a mixed solution the waves for Co and Ni were therefore well developed and separated in the former base electrolyte. The polarograms in urea-hydrazine were, however, of little analytical use because of the washing away of the Ni wave due to the presence of even small amounts of cobalt.
Zusammenfassung Das polarographische Verhalten von Nickel und Kobalt in Harnstoff-Pyridin- und Harnstoff-Hydrazinlösung wurde untersucht und der Einfluß des pH-Wertes, der Leitsalzkonzentration sowie der Gegenwart verschiedener anderer Ionen festgestellt. Bei pH 6,0 bzw. 5,0 wurden für beide Elemente gut ausgebildete Polarogramme erhalten. Es wurde versucht, die erhaltenen Ergebnisse zur Trennung der beiden Ionen zu benutzen. In Harnstoff-Pyridinlösung beträgt der Unterschied der beiden Halbstufenpotentiale mehr als –0,3 V und man erhält gut ausgebildete und voneinander getrennte Stufen. In Harnstoff-Hydrazinlösung dagegen beträgt der Unterschied nur –0,2 V oder etwas weniger, selbst unter optimaler Bedingungen, und die Ni-Stufe wird schon durch kleine Kobaltmengen beeinträchtigt.相似文献
4.
Consider a family of stars. Take a new vertex. Join one end-vertex of each star to this new vertex. The tree so obtained is known as abanana tree. It is proved that the banana trees corresponding to the family of stars
- (K1,1, K1,2,…, K1,t ?1, (α + l) K1,t, K1,t + 1, …, K1,n), α ? 0
- (2K1,1, 2K1,2,…, 2K1,t? 1, (α + 2)K1,t, 2K1,t + 1, …, 2K1,n), 0 ? α <t and
- (3K1,t, 3K1,2, …, 3K1,n) are graceful.
5.
Summary Procedures have been described for the quantitative determination of thiourea and its methyl derivatives, wherein iodate, permanganate, and ceric sulphate have been used as direct titration solution, either following preoxidation by alkali hypoiodite via (ICI + KOH) or in case of thiourea, by iodine bromide method. Apart from using standard oxidants the methods have an added advantage of a high conversion factor due to oxidation of sulphur to sulphate. Alternative physical methods of detecting the end point is an added feature of these procedures.The authors wish to express their grateful thanks to Dr. S. S. Joshi, D. Sc. (London), for his kind interest in the work. 相似文献
6.
Summary An amperometric titration of calcium with selenite is described. Barium, strontium, and other cations forming insoluble selenites interfere, but magnesium does not. The method is rapid and suitable for routine analysis, the error being less than 10 parts per 1000 over the range 50 to 70 mg of calcium.
Zusammenfassung Ein amperometrisches Titrationsverfahren für Calcium mit Selenit wurde beschrieben. Barium, Strontium und andere Kationen, die unlösliche Selenite bilden, stören, nur Magnesium nicht. Das Verfahren ist rasch und für Routineanalysen geeignet. Im Bereich zwischen 50 und 70 mg Calcium ist der Fehler geringer als 1% relativ.
Résumé On décrit un titrage ampérométrique du calcium par l'ion sélénite. Le baryum, le strontium et les autres cations formant des sélénites insolubles interfèrent, excepté le magnésium. La méthode est rapide et convient à l'analyse en série, l'erreur étant inférieure à 10 parties pour 1000 dans le domaine de 50–70 mg de calcium.相似文献
7.
Summary An extension of the two stage titration of ascorbic acid against iodate to the determination of iodine and iodide in a solution is described. A known excess of ascorbic acid, standardized against iodate, is added to a mixed iodine and iodide solution and the excess ascorbic acid together with the total iodide is titrated against the same iodate to the two end points under controlled conditions of acidity. The differential method of calculation gives the amount of iodine and iodide with a blank and a direct titration. The accuracy of the results provides a useful evidence for the mechanism suggested for the two stage titration of ascorbic acid against iodate.Our sincere thanks are due to Professor S. S. Joshi for kind interest in the work. 相似文献
8.
G. S. Deshmukh M. G. Bapat E. Balakrishnan M. C. Eshwar 《Fresenius' Journal of Analytical Chemistry》1959,170(2):381-383
Summary A new procedure for the quantitative determination of Ag, Hg and Pb has been described. This is based on the precipitation, under appropriate conditions of their normal selenites and titrating amperometrically the excess SeIV against NaOBr after filtering the precipitate. In this respect the method is almost analogous to the volumetric determination of the above metals after precipitating their pyridine thiocyanate complexes.Sincere thanks of the authors are due to Prof. S. S. Joshi for kind interest in the work, and to the National Institute of Sciences of India for an award of a fellowship to one of them (M. G. B.). 相似文献
9.
Subhash Deshmukh Wayne P. Hess 《Journal of photochemistry and photobiology. A, Chemistry》1994,80(1-3):17-21
Jet-cooled phosphorus trichloride, carbon tetrachloride, chloroform and molecular chlorine are photodissociated in the UV wavelength range 235–238 nm. Chlorine atom photofragments Cl (2P3/2) and Cl* (2P1/2) are detected via resonance-enhanced (2+1) ionization throughout the 232–238 nm wavelength region. The relative Cl* yields, φ*=[Cl*]/([Cl]+[Cl*]), are measured for both 35Cl and 37Cl isotopes using the two-photon atomic transitions at 235.3 nm for Cl and 237.8 nm for Cl*. Preliminary results indicate that the Cl* yields are different for the two isotopes for some of the precursors. In addition, we obtained the two-photon oscillator strength of the Cl transition at 237.7 nm relative to the Cl* transition at 237.8 nm. The advantage of using the two-photon Cl transition at 237.7 nm for quantum yield measurements is discussed. 相似文献
10.
Summary Pb, Tl, Bi and Sb yield well defined polarograms in 1 M ethylenediamine in presence of 3% mannitol, with half-wave potentials at – 0.71 V, – 0.51 V, – 0.60 V and – 1.10 V, respectively. Only Pb and Tl develop maxima which can be suppressed by 0.02% gelatin. Presence of mannitol prevents the precipitation of Pb, Bi, and Sb in the alkaline solution. Simultaneous determinations of Pb/Tl, Bi/Sb, and Pb/Sb can be carried out.
Polarographische Bestimmung von Pb, Tl, Bi und Sb in Äthylendiamin in Gegenwart von Mannit
Zusammenfassung Gut ausgebildete Polarogramme kann man von diesen Elementen in 1 M Äthylendiamin in Gegenwart von 3% Mannit erhalten. Die Halbstufenpotentiale liegen bei – 0,71 V (Pb), – 0,51 V (Tl), – 0,60 V (Bi) und – 1,10 V (Sb). Maxima, die im Falle von Pb und Tl gebildet werden, können durch 0,02% Gelatine unterdrückt werden. Durch Mannit wird die Fällung von Pb, Bi, und Sb in der alkalischen Lösung verhindert. Simultanbestimmungen von Pb/Tl, Bi/Sb und Pb/Sb sind möglich.
Our sincere thanks are due to Dr. G. B. Singh, Professor and Head, Department of Chemistry, B.H.U. for providing the necessary facilities. 相似文献