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61.
The thermal decomposition of MgCl2·6H2O (non-dried and partly dried) and the kinetics of the process were studied by DTA, TG, DTG, IR, X-ray diffraction and chemical analysis of Mg and Cl. The reactions which occurred in the course of the thermal analysis were identified as dehydration (in steps), thermal hydrolysis of MgCl2·H2O and dehydrochloridization of magnesium hydroxy chlorides. Melting of the phases MgCl2·6H2O, MgCl2·4H2O and MgCl2 was also identified in the thermal curves. Thermal weight loss continued up to 800 °C in flowing air or nitrogen, but only up to 700 °C in static air. MgO was the end-product of thermal treatment in both cases.The kinetic parameters of the reaction, the activation energyE, pre-exponential factorA and apparent order of reactionb, were computed by several methods. The activation energy and the apparent reaction order of dehydration were found to increase with decreasing hydration number of the Mg. The dehydrochloridization process had the highest activation energy.
The authors express their appreciation to Dr. Jacob Nathan and Mr. Yoetz Deutch from th Geological Survey, Jerusalem, for the use of the thermal analysis instrument and for useful discussion, and to Mrs. Sarah Erlich from the same institute, for the chemical analysis. The financial support by Everyman's University, Tel-Aviv, and by the Hebrew University of Jerusalem is acknowledged. 相似文献
Zusammenfassung Die thermische Zersetzung von MgCl2·6H2O (nicht und teilweise getrocknet) und die Kinetik dieses Prozesses wurden mittels DTA, TG, DTG, IR, Röntgendiffraktometrie und chemischer Analyse von Mg und Cl untersucht. Die im Verlaufe der thermischen Analyse vor sich gehenden Reaktionen sind Dehydratisierung (in Schritten), thermische Hydrolyse von MgCl2·H2O und Chlorwasserstoffaustritt aus Magnesiumhydroxychloriden. Das Schmelzen der Phasen MgCl2·6H2O, MgCl2·4H2O und MgCl2 ist in den thermischen Kurven ebenfalls zu erkennen. Im Luft- und Stickstoffstrom erfolgt ein Gewichtsverlust bis 800 °C, in statischer Luftatmosphäre dagegen nur bis 700 °C. MgO war in beiden Fällen Endprodukt der thermischen Behandlung. Die kinetischen Parameter der Reaktion (AktivierungsenergieE, präexponentieller FaktorA, scheinbare Reaktionsordnungb) wurden nach verschiedenen Methoden berechnet. Aktivierungsenergie und scheinbare Reaktionsordnung der Dehydratisierung nehmen mit abnehmendem Hydratationsgrad des Mg zu. Die Chlorwasserstoffabspaltung erfordert die höchste Aktivierungsenergie.
, , , , ( ) . : ( ), . , . 800 °C, - 700 °C. B . , . , . .
The authors express their appreciation to Dr. Jacob Nathan and Mr. Yoetz Deutch from th Geological Survey, Jerusalem, for the use of the thermal analysis instrument and for useful discussion, and to Mrs. Sarah Erlich from the same institute, for the chemical analysis. The financial support by Everyman's University, Tel-Aviv, and by the Hebrew University of Jerusalem is acknowledged. 相似文献
62.
The propagating mode solutions for a medium with an exponentially decaying gain profile are obtained. The mode profiles and the wavefronts were calculated numerically. The result explains satisfactorily the far field distribution observed in some of our new lasers. 相似文献
63.
The possibility of using Bragg reflection to obtain lossless confined propagation in slabs with a lower dielectric constant than that of the surrounding media is proposed and analyzed. 相似文献
64.
Photoresist gratings with variable period have been fabricated by recording the interference pattern of a collimated laser beam with a converging one. The period variation as a function of position, as well as the wavelength dependent focal properties of the gratings, has also been analyzed. 相似文献
65.
66.
The propagation of an optical pulse in a coupled-resonator optical waveguide may be calculated nonperturbatively to all orders of dispersion, in the conventional tight-binding approximation, even though the dispersion relationship is nonlinear. Working in this framework, we discuss limits of the physical parameters and approximations to the exact formulation that highlight the conditions under which pulse distortion can be minimized. The results are fundamental to the design of coupled-resonator optical waveguides and are also relevant to other applications of the tight-binding method. 相似文献
67.
We present a general proof of the distortion-correction theorem, that is, of the possibility of correcting wave distortion by the technique of optical phase conjugation. The proof is valid for fully vectorial nonparaxial propagation in the presence of a tensorial refractive-index perturbation and backscattering of the incident field. 相似文献
68.
Yu. E. Titarenko V. F. Batyaev A. Yu. Titarenko M. A. Butko K. V. Pavlov S. N. Florya R. S. Tikhonov V. M. Zhivun A. V. Ignatyuk S. G. Mashnik S. Leray A. Boudard J. Cugnon D. Mancusi Y. Yariv K. Nishihara N. Matsuda H. Kumawat G. Mank W. Gudowski 《Physics of Atomic Nuclei》2011,74(4):573-579
The cross sections for the production of 148Gd in natW and 181Ta targets irradiated by 0.4-, 0.6-, 0.8-, 1.2-, 1.6-, and 2.6-GeV protons at the ITEP accelerator complex have been measured by direct α spectrometry without chemical separation. The experimental data have been compared with the data obtained at other laboratories and with the theoretical simulations of the yields on the basis of the BERTINI, ISABEL, CEM03.02, INCL4.2, INCL4.5, CASCADE07, and PHITS codes. 相似文献
69.
Yu. E. Titarenko V. F. Batyaev A. Yu. Titarenko M. A. Butko K. V. Pavlov S. N. Florya R. S. Tikhonov V. M. Zhivun A. V. Ignatyuk S. G. Mashnik S. Leray A. Boudard J. Cugnon D. Mancusi Y. Yariv K. Nishihara N. Matsuda H. Kumawat G. Mank W. Gudowski 《Physics of Atomic Nuclei》2011,74(4):537-550
The cross sections for nuclide production in thin 93Nb and natNi targets irradiated by 0.04- to 2.6-GeV protons have been measured by direct γ spectrometry using two γ spectrometers with the resolutions of 1.8 and 1.7 keV in the 60Co 1332-keV γ line. As a result, 1112 yields of radioactive residual nuclei have been obtained. The 27Al(p, x)22Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations. 相似文献
70.
We show the feasibility of producing a low-mode all-fiber combiner fabricated from a large core and extremely small NA fibers. Although these fibers support multiple modes, the combiner that we produce can be operated nearly at the single mode regime while preserving the brightness of the combined beam almost perfectly with respect to the inputs. The M-square parameter of the combined beam was 2.3 and the power transfer efficiency was close to 100%. Such an all-fiber beam combining device is a rugged solution for high-brightness, high-efficiency beam delivery. 相似文献