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51.
52.
We have successfully produced a laser pulse with a peak power of 0.85 PW for a pulse duration of 33 fs in a four-stage Ti:sapphire amplifier chain based on chirped-pulse amplification. To our knowledge this result represents the highest peak power pulses yet produced in any Ti:sapphire chirped-pulse amplification system. 相似文献
53.
Tetsuya Kiriyama Mayumi Haraguchi Rokuro Kuroda 《Fresenius' Journal of Analytical Chemistry》1981,307(5):352-355
Summary Traces of titanium in sea water have been preconcentrated by anion-exchange from acidified samples in the presence of thiocyanate. Titanium adsorbs strongly on a column of Amberlite CG 400 (SCN–) and can be stripped easily by elution with 2 M hydrochloric acid — 1.5% hydrogen peroxide solution. Titanium in the effluent is determined spectrophotometrically with diantipyrylmethane as colour reagent. The combined method allows to determine traces of titanium very selectively and sensitively in sea water as well as non-saline water on a 41 sample basis. The method yields a coefficient of variation of 7% at a titanium level of 0.4 g per l.
Kombinierte Anionenaustauscher-Trennung und spektralphotometrische Bestimmung von Titanspuren in Meerwasser
Zusammenfassung Titanspuren wurden in Gegenwart von Thiocyanat durch Anionenaustausch aus der angesäuerten Probe angereichert. Titan wird an Amberlite CG 400 (SCN–) stark adsorbiert und kann durch Elution mit 2M HCl — 1,5% H2O2 leicht abgelöst werden. Im Eluat wird es spektralphotometrisch mit Diantipyrylmethan bestimmt. Die kombinierte Methode gestattet eine selektive und empfindliche Bestimmung in einer 41-Probe von Meer- oder auch Süßwasser. Für einen Gehalt von 0,4 g Ti/l beträgt der Variationskoeffizient 7%.相似文献
54.
Harumitsu Nishikawa 《Applied Surface Science》2009,255(16):7468-7470
Decomposition of gaseous toluene on thermally-excited activated titanium dioxide (TiO2) was investigated using a simple flow system. The decomposition of toluene on the TiO2 bead was 92% at 400 °C. The irregular phenomena in the toluene decomposition at around 300 °C seemed to be due to the coloration of the TiO2 bead. Electron spin resonance (ESR) measurement at high temperatures was carried out using the heating unit. Since the g-value of the signal was 1.996, the existence of Ti3+ in TiO2 material was confirmed. That is, oxygen vacancy generated by thermally-excitation of TiO2, and the reaction activity of the TiO2 bead for gaseous toluene must be due to spins on the material. 相似文献
55.
Kiriyama H Mori M Nakai Y Yamamoto Y Tanoue M Akutsu A Shimomura T Kondo S Kanazawa S Daido H Kimura T Miyanaga N 《Optics letters》2007,32(16):2315-2317
We describe a compact, reliable, high-power, and high-contrast noncollinear optical parametric chirped-pulse amplifier system. With a broadband Ti:sapphire oscillator and grating-based stretching and compression, the chirped pulses are amplified from 0.1 nJ to 122 mJ in type I beta-barium borate optical parametric chirped-pulse amplifiers with a total gain of over 10(9) at 10 Hz repetition rate. Pulse compression down to 19-fs duration achieved after amplification indicates a peak power of 3.2 TW at an average power of 0.62 W. The prepulse contrast is measured to be less than 10(-8) on picosecond time scales. 相似文献
56.
The chemical behavior of 1-adamantylnitrenium ion seems to be not known much compared to 1-adamantylcarbinyl cation,2 though one example of the rearrangement of 1-adamantylnitrenium ion to 4-azahomoacamantyl ion has been reported recently by Kovacic et al in the reaction of 1-M,N-dichloroaminoadamantane with aluminum chloride.3 From our interest in the reactivity and rearrangement aptitude of 1-adamantylnitrenium ion, we investigated the reactions of various N-substituted N-chloro-1-adamantylamine derivatives with aluminum chloride. This communication deals with the preliminary results which indicated that the reactions of 1-adamantylnitrenium ion are much affected by the N-substituents and also by the solvents used. 相似文献
57.
58.
A combined preconcentration-photometric determination technique has been worked out for trace concentration of tin in fresh and sea waters. After refluxing the sample acidified to 1M HCl for 2 h, tin is preconcentrated by anion-exchange in the presence of thiocyanate and recovered by elution with dilute HNO3. Tin is then generated as stannane, caught in permanganate solution, and determined spectrpphotometrically with phenylfluorone. The results are quoted on the determination of tin in several fresh and sea waters in the order of submicrogram of tin per litre. The results for tin are in good agreement with those obtained for these samples by manganese dioxide coprecipitation-hydride generation-phenylfluorone spectrophotometric method that is also newly developed. 相似文献
59.
Proton spin-lattice relaxation rate has been measured at room temperature in the impurity-doped (CH3)4NMn(1-x)CuxCl3 for X = 0.04, 0.1 and 0.17. The result for Hz. snfc;chain-axis as a function of resonance frequency clearly shows that the spectral density of the spin fluctuations in the impure system remains to have the characteristics 1-D diffusive term (ω-), with a slower rate of the spin diffusion in accordance with the theory by Richards. The result for H⊥ chain-axis indicates, however, the existence of a singularity of the fluctuations near ω = 0. 相似文献
60.
Several 4-oxa- and -aza-bird-cage compounds were prepared by transannular cyclizations of pentacyclo[6.2.1.0.2,70.4,1005,9]undecan-3,6-dione (3). Diol derivatives of 3 cyclized to afford the corresponding 4-oxa-bird-cage derivatives such as 9, 16a and 16b. The corresponding 3-keto-6-ol derivatives (6, 10a and 10b) did not cyclize transannularly, while 3-imino-6-ol, 3-keto-6-amino, and 3- imino-6-amino type derivatives cyclized to afford 3-substituted 4-oxa- and -aza-bidr-cage compounds such as 12, 14 and 18. The transannular cyclization reactivity in the 3 system has been compared with that in the bicyclo[3.3.1]nona-3,7-dione system (1). 相似文献