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Summary On the basis of the completely-optimized S0 and S2 molecular geometries of pyrene the vibrational structure of the electronic S2S0 transition was calculated within both the Condon approach and the first-order Herzberg-Teller approach. The theoretical results demonstrate the significant influence of vibronic coupling. An analysis of the active vibrational modes is given. The theory-experiment comparison within the Herzberg-Teller approach is satisfactory. 相似文献
5.
One of the major applications for dielectrophoresis is selective trapping and fractionation of particles. If the surrounding medium is of low conductivity, the trapping force is high, but if the conductivity increases, the attraction decreases and may even become negative. However, high-conductivity media are essential when working with biological material such as living cells. In this paper, some basic calculations have been performed, and a model has been developed which employs both positive and negative dielectrophoresis in a channel with interdigitated electrodes. The finite element method was utilized to predict the trajectories of Escherichia coli bacteria in the superpositioned electrical fields. It is shown that a drastic improvement of trapping efficiency can be obtained in this way, when a high conductivity medium is employed. 相似文献
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K. Schweiger A. Fuchsgruber Prof. Dr. G. Zigeuner 《Monatshefte für Chemie / Chemical Monthly》1977,108(1):243-255
Tetrahydro-6-hydroxy-trimethyl-1,3-thiazine-2-thione (1) reacts with secondary amines via the dialkylammonium-3-oxoalkyldithiocarbamate3, either via isothiocyanates6 to 4-dialkylaminodihydro-2(1H)-pyridinethiones7 or to dialkylammonium dithiocarbamates (13), depending on the amine used and the reaction conditions. Subsequently, 6-dialkylaminotetrahydro-1,3-thiazine-2-thiones11 or tetrahydro-6-mercapto-1,3-thiazine-2-thione10 are formed. On being heated to reflux,11 reacts to pyridinethione7 and 4-dialkylaminodihydrothiopyranthione19. With secondary amines only13 is formed from tetrahydro-6-hydroxytetramethyl-1,3-thiazine-2-thione20. The reaction of dihydrotrimethyl-1,3-thiazine-2-thione21 with secondary amines leads to N,N-dialkylthioureas16 or dialkylammonium thiocyanates17 and with dialkylformamides 4-dialkylaminodihydropyridinethiones7 are formed. Dihydrotetramethyl-1,3-thiazine-2-thione24 reacts neither with secondary amines nor with dialkylformamides. 相似文献
7.
The rearrangement of 1-alkyl- and 1-aryldihydro-6-methyl-2(1H)-pyrimidinethiones (1 a) or-ones (1 b) and of methylene compounds (2a, 2b) resp., to 4-alkylamino- and 4-arylaminodihydro-2(1H)-pyridinethiones (4 a) or-ones (4 b) takes place via the corresponding 3-alkylamino- and 3-aryl-amino-3-butenylisothiocyanates (3 a) or-isocyanates (3 b). Dialkylamino-dihydro-2(1H)-pyridinethiones (10) are formed by heating dihydro-6-methyl-2(1H)-pyrimidinethiones (6 a) and 3,4-dihydro-6-methyl-1,3-thiazin-2-thiones (6 b) with dialkylformamides and by the reaction of secondary amines with tetrahydro-6-hydroxy-6-methyl-1,3-thiazin-2-thiones (5 a), with N,N-dialkyl-N-(3-oxobutyl)-thioureas (7) and 3-oxobutyl isothiocyanates (8). A general method for the preparation of10 is the reaction of dialkylammoniumrhodanides12, N,N-dialkylthioureas13 and dialkylammonium chlorides and KCNS, resp., with 3-alken-2-ones14 and 4-hydroxy-2-alkanones15, resp. Methyl ketones such as acetone, which readily undergo the aldol condensation, behave analogously. The reactions described take place via the intermediate aminoalkenyl isothiocyanates (9). 相似文献
8.
Ohne ZusammenfassungI.H. Schmid undG. Muhr, Ber. dtsch. chem. Ges.70, 421 (1937); II.H. Schmid, Z. Elektrochem.43, 626 (1937); III.H. Schmid, Atti X. Congr. internat. Chim. Roma2, 484 (1938); IV.H. Schmid undA. Woppmann, Mh. Chem.83, 346 (1952); V. und VI.H. Schmid undR. Pfeifer, Mh. Chem.84, 829, 842 (1953); VII.H. Schmid, Mh. Chem.85, 424 (1954); zusammenfassender Ber.:H. Schmid, Chemiker-Ztg.78, 565, 683 (1954); VIII.H. Schmid, Mh. Chem.86, 668 (1955); IX.H. Schmid undA. F. Sami, Mh. Chem.86, 904 (1955); X.H. Schmid undE. Hallaba, Mh. Chem.87, 560 (1956); XI.H. Schmid undA. Woppmann, Mh. Chem.88, 411 (1957);H. Schmid, Mh. Chem.88, 161, 344 (1957); XII.H. Schmid undM. G. Fouad, Mh. Chem.88, 631 (1957);H. Schmid, Österr. Pat. 191 399, Kl. 12e2 (Juni 1957);H. Schmid, Chemiker-Ztg.81, 603 (1957); XIII. und XIV.H. Schmid undCh. Essler, Mh. Chem.88, 1110 (1957);90, 222 (1959); XV.H. Schmid undA. Woppmann, Mh. Chem.90, 903 (1959); XVI.H. Schmid undCh. Essler, Mh. Chem.91, 484 (1960); XVII.H. Schmid undG. Muhr, Mh. Chem.91, 1198 (1960);H. Schmid, Mh. Chem.92, 174 (1961). 相似文献
9.
Henrik Land Alina Sekretareva Ping Huang Holly J. Redman Brigitta Nmeth Nakia Polidori Lívia S. Mszros Moritz Senger Sven T. Stripp Gustav Berggren 《Chemical science》2020,11(47):12789
[FeFe]-hydrogenases are known for their high rates of hydrogen turnover, and are intensively studied in the context of biotechnological applications. Evolution has generated a plethora of different subclasses with widely different characteristics. The M2e subclass is phylogenetically distinct from previously characterized members of this enzyme family and its biological role is unknown. It features significant differences in domain- and active site architecture, and is most closely related to the putative sensory [FeFe]-hydrogenases. Here we report the first comprehensive biochemical and spectroscopical characterization of an M2e enzyme, derived from Thermoanaerobacter mathranii. As compared to other [FeFe]-hydrogenases characterized to-date, this enzyme displays an increased H2 affinity, higher activation enthalpies for H+/H2 interconversion, and unusual reactivity towards known hydrogenase inhibitors. These properties are related to differences in active site architecture between the M2e [FeFe]-hydrogenase and “prototypical” [FeFe]-hydrogenases. Thus, this study provides new insight into the role of this subclass in hydrogen metabolism and the influence of the active site pocket on the chemistry of the H-cluster.Characterization of a group D putative sensory [FeFe]-hydrogenase reveals how the active site can be tuned to decrease CO inhibition and increase stability of a reduced H-cluster while retaining the ability to catalyze H+/H2 interconversion. 相似文献
10.
Feichtinger Gustav Hartl Richard F. Kort Peter M. Seidl Andrea Wrzaczek Stefan 《Journal of Optimization Theory and Applications》2022,194(3):878-895
Journal of Optimization Theory and Applications - This paper considers a capital accumulation game where the installation costs of investments are lowered by the firm’s own capital stock... 相似文献