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151.
152.
A novel differential thermoanalytical technique is described and discussed with regard to function, operation, performance, theory and application. Information is provided about the nature of the internal processes taking place at the time of absorption or release of energy. Notable features of the technique include high sensitivity and independence of a reference sample.
We wish to acknowledge support of this research by the National Research Council of Canada and Dalhousie University, Halifax. 相似文献
Zusammenfassung Eine neue differentialthermoanalytische Technik wird hinsichtlich ihrer Funktion, Arbeitsweise, Leistung, Theorie und Anwendung beschrieben. Es wird über die Beschaffenheit der inneren Vorgänge bei der Energie-Absorption oder -Freisetzung berichtet. Vorteile der neuen Technik sind die hohe Empfindlichkeit und die Unabhängigkeit von der Referenzprobe.
Résumé On décrit et discute une nouvelle technique d'ATD en considérant sa fonction, son utilisation, ses possibilités, sa théorie et son application. On indique les processus internes qui se produisent lors de l'absorption ou de la libération d'énergie. Les principales caractéristiques de la technique se rapportent à la sensibilité élevée et à l'indépendance de l'échantillon de référence.
, , , , , . .
We wish to acknowledge support of this research by the National Research Council of Canada and Dalhousie University, Halifax. 相似文献
153.
Solid phase microextraction with matrix assisted laser desorption/ionization introduction to mass spectrometry and ion mobility spectrometry 总被引:1,自引:0,他引:1
Solid phase microextraction (SPME) with matrix assisted laser desorption/ionization (MALDI) introduction was coupled to mass spectrometry and ion mobility spectrometry. Nicotine and myoglobin in matrix 2,5-dihydroxybenzonic acid (DHB), enkephalin and substance P in alpha-cyano-4-hydroxy cinnaminic acid were investigated as the target compounds. The tip of an optical fiber was silanized for extraction of the analytes of interest from solution. The optical fiber thus served as the sample extraction surface, the support for the sample plus matrix, and the optical pipe to transfer the laser energy from the laser to the sample. The MALDI worked under atmospheric pressure, and both an ion mobility spectrometer and a quadrupole/time-of-flight mass spectrometer were used for the detection of the SPME/MALDI signal. The spectra obtained demonstrate the feasibility of the SPME with MALDI introduction to mass spectrometry instrumentation. 相似文献
154.
Let T and be arbitrary nonnegative, irreducible, stochastic matrices corresponding to two ergodic Markov chains on n states. A function κ is called a condition number for Markov chains with respect to the (α, β)–norm pair if . Here π and are the stationary distribution vectors of the two chains, respectively. Various condition numbers, particularly with respect
to the (1, ∞) and (∞, ∞)-norm pairs have been suggested in the literature. They were ranked according to their size by Cho
and Meyer in a paper from 2001. In this paper we first of all show that what we call the generalized ergodicity coefficient
, where e is the n-vector of all 1’s and A
# is the group generalized inverse of A = I − T, is the smallest condition number of Markov chains with respect to the (p, ∞)-norm pair. We use this result to identify the smallest condition number of Markov chains among the (∞, ∞) and (1, ∞)-norm
pairs. These are, respectively, κ
3 and κ
6 in the Cho–Meyer list of 8 condition numbers. Kirkland has studied κ
3(T). He has shown that and he has characterized transition matrices for which equality holds. We prove here again that 2κ
3(T) ≤ κ(6) which appears in the Cho–Meyer paper and we characterize the transition matrices T for which . There is actually only one such matrix: T = (J
n
− I)/(n − 1), where J
n
is the n × n matrix of all 1’s.
This research was supported in part by NSERC under Grant OGP0138251 and NSA Grant No. 06G–232. 相似文献
155.
Jor-Ting Chan Chi-Kwong Li Nung-Sing Sze 《Proceedings of the American Mathematical Society》2007,135(4):977-986
Let be the set of complex matrices, and for every , let denote the spectrum of . For various types of products on , it is shown that a mapping satisfying for all has the form for some invertible and scalar . The result covers the special cases of the usual product , the Jordan triple product , and the Jordan product . Similar results are obtained for Hermitian matrices.
156.
Xue J Guo Z Chan PY Chu LM But TY Phillips DL 《The journal of physical chemistry. A》2007,111(8):1441-1451
A time-resolved resonance Raman investigation of the reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide in a mixed aqueous solvent is presented. The reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide in the mixed aqueous solution generates two new species on the microsecond time scale. One of these species is identified as 2,2'-azobisfluorene, and the other species is tentatively assigned to a 1,4-bis-(2,2'-fluorenyl)-tetrazadiene cation intermediate. The structure and properties of these two species are briefly discussed. The reaction of the 2-fluorenylnitrenium ion with 2-fluorenylazide is also briefly compared to that of the 2-fluorenylnitrenium ion reactions with guanosine and water. 相似文献
157.
Carbon nanotube mode lockers with enhanced nonlinearity via evanescent field interaction in D-shaped fibers 总被引:1,自引:0,他引:1
We demonstrate a novel passive mode-locking scheme for pulsed lasers enhanced by the interaction of carbon nanotubes (CNTs) with the evanescent field of propagating light in a D-shaped optical fiber. The scheme features all-fiber operation as well as a long lateral interaction length, which guarantees a strong nonlinear effect from the nanotubes. Mode locking is achieved with less than 30% of the CNTs compared with the amount of nanotubes used for conventional schemes. Our method also ensures the preservation of the original morphology of the individual CNTs. The demonstrated pulsed laser with our CNT mode locker has a repetition rate of 5.88 MHz and a temporal pulse width of 470 fs. 相似文献
158.
Nga Sze Ieong Author Vitae Author Vitae 《Journal of organometallic chemistry》2008,693(5):802-807
Although extensive previous studies have shown that strained [1]ferrocenophanes predominantly undergo ring-opening chemistry at the bridging atom E-cyclopentadienyl (E-Cp) bond, recent reports have highlighted that reactivity at the Fe-Cp bond can also occur, especially on photoactivation. We provide an overview of recent results from our group and those of other researchers. In addition, the development of photocontrolled living polymerizations of sila[1]ferrocenophanes using Fe-Cp bond cleavage chemistry is described. 相似文献
159.
160.
A general procedure for free porphyrin catalyzed direct C-H arylation of benzene was demonstrated. This air tolerant, transition-metal-free process provides a promising system for cheap and efficient synthesis of biaryls in a user-friendly approach. 相似文献