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81.
The influence on the mass transfer in liquid-liquid extraction was investigated during droplet formation in a quiescent aqueous continuous phase for the two transition components, acetone and acetonitrile, in toluene. Both transition components have similar characteristics. However, an approximately eight times slower mass transfer of a droplet hanging on a capillary in relation to a rising droplet could be observed. The droplet formation time and the initial solute concentration are decisive for the mass transfer behaviour. A lower volumetric flow leads to slower droplet formation and a higher specific mass transfer area enhancing mass transfer, which is visualized via laser induced fluorescence (LIF). Additionally, as expected, higher initial solute concentrations promote Marangoni turbulences and thus mass transfer, which is measured via confocal Raman spectroscopy inside a fixed hanging droplet. 相似文献
82.
Nitric oxide and myoglobins 总被引:1,自引:0,他引:1
83.
Summary
This article reports the synthesis of novel hydrophilic end-branched poly(ethylene glycol)s, in aqueous media by atom transfer
radical polymerization (ATRP). Poly(ethylene glycol)s with molecular weights 10,000 and 16,000 were end-functionalized and
used as bifunctional initiators for the polymerization of a poly(ethylene glycol) macromonomer with a molecular weight of
2,000 (PEGMA), either by aqueous ATRP or in a watedmethanol (l/l V/V) mixture. For both macroinitiators a DP of 10 was the
target, giving an average of 5 branches in each end. The rates of polymerization were of the same order of magnitude when
the polymerizations were initiated by either of the two macroinitiators in watedmethanol (l/l V/V). When a bifunctional oligo(ethy1ene
glycol) initiator (Mn = 600) was used to study the polymerization of PEGMA in water/methanol a reduction in the rate of polymerization was observed
indicating an influence of the molecular weight of the initiator on the rate of polymerization.
Received 25 Maich 2002/Revised 8 November 2002/Accepted 8 November 2002
Correspondence to Jorgen Kops 相似文献
84.
Large-Scale Hydrogen Production 总被引:3,自引:0,他引:3
There is a growing need for hydrogen in processing heavier and dirtier fossil fuels and a future hydrogen economy is widely suggested as the next generation fuel/energy source once fossil fuels diminish in availability. Sustainable fuels are still regarded as too expensive given the large amounts of natural gas and a projected, ample supply of fossil fuels beyond the next twenty-plus years. Today, the steam reforming of hydrocarbons is the most favorable route to H2. If CO2 sequestration were ever to become widely practiced, fossil fuels would continue to play an important role in the future hydrogen economy. 相似文献
85.
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88.
Hong?ZhangEmail author Lars?Saaby?Pedersen Dorther?Kristensen Jens?Adler-Nissen Hans?Christian Holm 《Journal of the American Oil Chemists' Society》2004,81(7):653-658
Lipozyme TL IM-catalyzed interesterification for the modification of margarine fats was carried out in a batch reactor at
70°C with a lipase dosage of 4%. Solid fat content (SFC) was used to monitor the reaction progress. Lipase-catalyzed interesterification,
which led to changes in the SFC, was assumed to be a first-order reversible reaction. Accordingly, the change in SFC vs. reaction
time was described by an exponential model. The model contained three parameters, each with a particular physical or chemical
meaning: (i) the initial SFC (SFC0), (ii) the change in SFC (ΔSFC) from the initial to the equilibrium state, and (iii) the reaction rate constant value (k). SFCo and ΔSFC were related to only the types of blends and the blend ratios. The rate constant k was related to lipase activity on a given oil blend. Evaluation of the model was carried out with two groups of oil blends,
i.e., palm stearin/coconut oil in weight ratios of 90∶10, 80∶20, and 70∶30, and soybean oil/fully hydrogenated soybean oil
in weight ratios of 80∶20, 65∶35, and 50∶50. Correlation coefficients higher than 0.99 between the experimental and predicted
values were observed for SFC at temperatures above 30°C. The model is useful for predicting changes in the SFC during lipase-catalyzed
interesterification with a selected group of oil blends. It also can be used to control the process when particular SFC values
are targeted. 相似文献
89.
Stefan Schafföner Jens Fruhstorfer Susann Ludwig Christos G. Aneziris 《Ceramics International》2018,44(8):9027-9036
This study investigated the cold isostatic pressing of coarse grained alumina refractories applying either a cyclic pressure increase or a cycling at maximum pressure. Additionally the effects of the maximum pressure and the particle size distribution on physical, mechanical and thermomechanical properties were analyzed. The cyclic pressure increase resulted in a slightly higher apparent density and lower apparent porosity. A cycling at maximum pressure decreased the median pore size to some extent. Remarkably, an optimized particle size distribution resulted in a lower apparent porosity, lower median pore size and in a higher Young's modulus before and after thermal shock together with a slightly lower relative decrease of the Young's modulus. A higher pressing pressure which decreased the apparent porosity did not affect the Young's modulus. Thus, apparently the optimized particle size distribution improved the particle packing which was associated with a smaller median pore size. This smaller pore size increased the number of pores relative to the total porosity, which then acted as points of crack initiation and crack deflection limiting the length of propagating cracks in case of thermal shock. Thus, tailoring the pore size distribution is a promising starting point to improve the thermomechanical properties of refractories. 相似文献
90.
Cover Picture: Selective Inhibitors of the Protein Tyrosine Phosphatase SHP2 Block Cellular Motility and Growth of Cancer Cells in vitro and in vivo (ChemMedChem 5/2015) 下载免费PDF全文