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51.
Carsten Thöne Jörg Laube Stefan Jäger 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):641-644
Organometallic tungsten selenido complexes of the type [cpW(CO)3]2Sem; m = 2 (1), 3 (2), 4 (3), can be easily synthesized via insertion of selenium into the alkali-metal tungsten bond of LiWcp(CO)3 in appropriate ratios and subsequent oxidation of the produced W-selenolates with O2/SiO2. In contrast, reactions of K2Se6 with [cpW(CO)3Cl] and 18-crown-6 in DMF lead to a mixture óf [cpW(CO)3]2Se4 (3), the η1 Se-bonded selenocarbamato complex [cpW(CO)3SeC(O)NMe2] (4) and the ionic complex [(18-crown-6)K]+[cpW(Se4)2]? (5). The crystal structures of 3 and 4 together with their 77Se NMR data are presented. 相似文献
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M. Jankov G. Løvoll H. A. Knudsen K. J. Måløy R. Planet R. Toussaint E. G. Flekkøy 《Transport in Porous Media》2010,84(3):569-585
The effects of seismic stimulation on the flow of two immiscible fluids in an elastic synthetic porous medium is experimentally
investigated. A wetting fluid is slowly evacuated from the medium, while a pressure oscillation is applied on the injected
non- wetting fluid. The amplitude and frequency of the pressure oscillations as well as the evacuation speed are kept constant
throughout an experiment. The resulting morphology of the invading structure is found to be strongly dependent on the interplay
between the amplitude and the frequency of the applied pressure oscillations and the elasticity of the porous medium. Different
combinations of these properties yield morphologically similar structures, allowing a classification of structures that is
found to depend on a proposed dimensionless number. 相似文献
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Sébastien Simon Stefan Theiler Agnethe Knudsen Gisle Øye Johan Sjöblom 《Journal of Dispersion Science and Technology》2013,34(5):632-640
We have studied the rheological properties of fumed silica particle-stabilized emulsions. Two particles of different polarity were considered, the first more hydrophilic “Aerosil R7200,” the second more hydrophobic “Aerosil R972.” These particles flocculate and probably form a network at the investigated concentration. The flow curves of emulsions stabilized by a single type of particles exhibit yield stress, shear-thinning behavior and thixotropy. Moreover they display rheological features typical of gels. These features are attributed to strengthening of the particle network by droplets. Moreover the rheological properties of w/o emulsions stabilized by hydrophobic are similar to the ones of o/w emulsions stabilized by hydrophilic particles. The rheological properties of o/w emulsions stabilized by mixtures of hydrophilic and hydrophobic particles have then been studied by keeping the total particle concentration constant and varying the mass ratio between particles. The results show that when the hydrophobic particle concentration increases, the viscosity and stability of emulsions decrease establishing evidence that the network is weakened due to preferential orientation of hydrophobic particles towards the oil phase. 相似文献
59.
Md Lutfor Rahman Jahimin Asik Sandeep Kumar Carsten Tschierske 《Liquid crystals》2013,40(11):1263-1270
Three banana‐shaped monomers, i.e. 2,7‐naphthalene bis[4‐(4‐allyloxyphenylazo)‐benzoate], 2,7‐naphthalene bis[4‐(4‐allyloxy‐3‐fluorophenylazo)benzoate] and 2,7‐naphthalene bis{4‐[4‐(10‐undecenyloxy)phenylazo]benzoate}, containing azobenzene as side arms, 2,7‐dihydroxynaphthalene as central units and terminal double bonds as polymerisable functional groups, were synthesised and their mesophase behaviour investigated. Polarizing optical microscopy and DSC measurements reveal that all compounds exhibit nematic mesophases. The absorption spectrum of the trans‐azobenzene groups displays a high‐intensity π–π* transition at about 365 nm and a low‐intensity n–π* transition at around 450 nm for all compounds. Hence, photochromism can be achieved by the introduction of the azo linkage to banana‐shaped liquid crystals molecules. 相似文献
60.
Tobias Dunaj Prof. Dr. Carsten von Hänisch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(69):e202202932
In this work, we report the preparation of multiple interpnictogen chain compounds with three consecutive pnictogen atoms and terminal Ar2Bi fragments (Ar=Ph, Mes). Symmetrical compounds of the form Ar2Bi−E(tBu)−Bi2Ar ( 1 : Ar=Ph, E=P; 2 : Ar=Ph, Mes, E=As) as well as ternary interpnictogen compounds of the form Ar2Bi−E1(tBu)−E2tBu2 (Ar=Ph, Mes; 4 : E1=P, E2=As; 5 : E1=P, E2=Sb; 6 : E1=As, E2=P) were prepared. The decomposition in solution at room temperature and under the influence of light was studied for compounds 1 – 6 . The reactivity of 1Ph and 2Ph with the small N-heterocyclic carbene 1,3,4,5-tetramethylimidazol-2-ylidene (Me2IMe) was also studied. In the case of 1Ph , the formation and consecutive decomposition of Me2IMe=PtBu ( 8 ) was observed in solution. Hence, it was shown that 1Ph can react as a “masked phosphinidene”. In the case of 2Ph , no reaction with Me2IMe was observed. All isolated compounds were analysed by NMR and IR spectroscopy, mass spectrometry, elemental analysis and single-crystal X-ray diffraction. 相似文献