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991.
Cracking of suspensions during drying is a common problem. While additives, for example, binders and surfactants, can mitigate this problem, some applications, such as printing conductive pastes or sintering green bodies, do not lend themselves to the use of additives. Capillary suspensions provide an alternative formulation without additives. In this work, we use simultaneous stress and weight measurements to investigate the influence of formulation and drying conditions. Capillary suspensions dry more homogeneously and with lower peak stresses, leading to an increased robustness against cracking compared. An increase in dry film porosity is not the key driver for the stress reduction. Instead, the capillary bridges, which create strong particle networks, resist the stress. Increasing the relative humidity enhances this effect, even for pure suspensions. While lower boiling point secondary liquids, for example, water, persist for very long times during drying, higher boiling point liquids offer further potential to tune the drying process. 相似文献
992.
Bioorthogonally Applicable Fluorescence Deactivation Strategy for Receptor Kinetics Study and Theranostic Pretargeting Approaches
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Steffen van der Wal Clarize M. de Korne Laurens G. L. Sand Danny M. van Willigen Prof. Pancras C. W. Hogendoorn Dr. Karoly Szuhai Dr. Fijs W. B. van Leeuwen Dr. Tessa Buckle 《Chembiochem : a European journal of chemical biology》2018,19(16):1758-1765
The availability of a receptor for theranostic pretargeting approaches was assessed by use of a new click‐chemistry‐based deactivatable fluorescence‐quenching concept. The efficacy was evaluated in a cell‐based model system featuring both membranous (available) and internalized (unavailable) receptor fractions of the clinically relevant receptor chemokine receptor 4 (CXCR4). Proof of concept was achieved with a deactivatable tracer consisting of a CXCR4‐specific peptide functionalized with a Cy5 dye bearing a chemoselective azide handle (N3‐Cy5‐AcTZ14011). Treatment with a Cy7 quencher dye (Cy7‐DBCO) resulted in optically silent Cy7‐[click]‐Cy5‐AcTZ14011. In situ, a >90 % FRET‐based reduction of the signal intensity of N3‐Cy5‐AcTZ14011 [KD=(222.4±25.2) nm ] was seen within minutes after quencher addition. In cells, discrimination between the membranous and the internalized receptor fraction could be achieved through quantitative assessment of quenching/internalization kinetics. Similar evaluation of an activatable tracer variant based on the same targeting moiety (Cy5‐S‐S‐Cy3‐AcTZ14011) was unsuccessful in vitro. As such, using the described deactivatable approach to screen membrane receptors and their applicability in receptor‐(pre‐)targeted theranostics can become straightforward. 相似文献
993.
Jörg Töpfer Timmy Reimann Thomas Schulz Arne Bochmann Beate Capraro Stefan Barth Andy Vogel Steffen Teichert 《International Journal of Applied Ceramic Technology》2018,15(3):716-722
Oxide multilayer thermoelectric generators (MLTEG) were fabricated, using the standard multilayer technology. Green tapes of p‐type La2CuO4 and n‐type Nd2CuO4 thermoelectric oxides were stacked with intermediate insulating glass layers. Electrical contacts between thermoelectric oxides were applied, using screen‐printing of AgPd paste, and multilayers were cofired at 1000°C. However, cofiring of four different materials turned out to be very challenging, and contact resistance problems frequently led to device malfunctions. We developed a new concept of a transversal multilayer thermoelectric generator (TMLTEG), which is characterized by a simple design. This generator is build up by stacking layers of a p‐ or n‐type thermoelectric oxide and printing stripes of AgPd paste onto the thermoelectric layers at an angle with respect to the temperature gradient. Transversal multilayer thermoelectric generators were fabricated using p‐type La2CuO4, or n‐type substituted CaMnO3; cofiring of the multilayer stacks was performed at 1000°C. The TMLTEG based upon p‐type lanthanum cuprate exhibits a power output of 7.8 mW at ?T= 200 K in the low temperature range of 25‐135°C. Materials issues, cofiring characteristics, design and the thermoelectric performance of multilayer TEGs will be discussed. 相似文献
994.
Interaction of slip‐ and flame‐spray coated carbon‐bonded alumina filters with steel melts
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Patrick Gehre Anne Schmidt Steffen Dudczig Jana Hubálková Christos G. Aneziris Nick Child Ian Delaney Gilbert Rancoule Duane DeBastiani 《Journal of the American Ceramic Society》2018,101(7):3222-3233
Ceramic foam filters play an essential role in the quest for cleanliness of cast steel parts as they facilitate turbulence reduction during mold filling as well as removal of nonmetallic inclusions. A coating on these filters is able to increase their strength and filtration efficiency by improving the adhesion of inclusions to the filter strands. In this study, Al2O3‐C filters were coated with an alumina slip via slip and flame spraying. The phase composition and the microstructure of the coatings were investigated before and after immersion into molten steel contained in a metal casting simulator. After contact with molten steel, Al2O3‐C reference filter shows intense decarburization which often influence the quality of cast steel parts due to formation of gas bubbles. Slip‐sprayed alumina coatings on such a filter promote the deposition of inclusions due to formation of a vitreous alumina layer but will also cause gas bubble formation as they exhibit a high porosity. Flame‐spray coatings have low porosity and hence, prevent formation of gas bubbles. Furthermore, they showed the highest reactivity toward the steel melt and hence, are recommended for filtration of cast products with a high demand on cleanliness. 相似文献
995.
Andreas Otto Stefan Rauh Steffen Ihlenfeldt Günter Radons 《The International Journal of Advanced Manufacturing Technology》2017,89(9-12):2613-2625
We study mechanical vibrations in milling with non-uniform pitch and variable helix tools. The process is modeled by a periodic delay differential equation with distributed delay, which takes into account, for example, the nonlinear cutting force behavior, the effect of runout, and the exact delay distribution due to the unequally spaced flutes. We present a new method for the identification of the chatter stability lobes from the linearized system that is based on the multifrequency solution. We give detailed remarks on the truncation of the resulting infinite dimensional matrices and the efficient numerical implementation of the method. Cutting tests for steel milling with a customary end mill with non-uniform pitch and variable helix angle and a conventional end mill with uniform pitch and constant helix angle are performed. The numerical and experimental results coincide well. They reveal a significant increase of the limiting depth of cut for the variable helix tool compared to the conventional tool. Moreover, we show that in contrast to conventional tools, for non-uniform pitch and variable helix tools, an exact model with time-varying coefficients, nonlinear cutting force behavior, and runout is necessary for an accurate prediction of the stability lobes. 相似文献
996.
Fabrication of a transversal multilayer thermoelectric generator with substituted calcium manganite
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Timmy Reimann Arne Bochmann Andy Vogel Beate Capraro Steffen Teichert Jörg Töpfer 《Journal of the American Ceramic Society》2017,100(12):5700-5708
The sintering behavior and thermoelectric performance of Ca0.99Gd0.01Mn0.99W0.01O3 was studied, and a multilayer thermoelectric generator was fabricated. The addition of CuO as sintering additive was found to be effective for the reduction in the sintering temperature from 1300°C to about 1000°C‐1050°C. Dense samples were obtained after firing at 1050°C, whereas some porosity remained after firing at 1000°C. Samples sintered at reduced temperature exhibit lower electrical conductivity, whereas the Seebeck coefficient S = ?150 μV/K at 100°C is not affected by lowering the sintering temperature. The figure of merit is ZT = 0.12 at 700°C for samples sintered at 1300°C; ZT = 0.08 and 0.03 were obtained for multilayer laminates sintered at 1050°C and 1000°C, respectively. A transversal multilayer thermoelectric generator (TMLTEG) was built by stacking layers of substituted CaMnO3 green tapes, and printing AgPd conductor stripes onto the thermoelectric layers at an angle of 30° relative to the direction of the heat flow. The multilayer stack was co‐fired at 1000°C. The TMLTEG has a power output of 2.5 mW at ?T= 200 K in the temperature interval of 25°C‐300°C. A meander‐like generator with larger power output comprising six TMTEGs is also presented. 相似文献
997.
998.
999.
1000.
Robert Braunsdorf Uwe Hener Gaby Przibilla Steffen Piecha und Armin Mosandl 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1993,197(1):24-28
Zusammenfassung Der Einfluß chromatographischer und technologischer Verfahren auf den13C-Isotopengehalt aromarelevanter Substanzen in Orangenölen wird untersucht. Um Fehlinterpretationen von Isotopendaten auszuschließen, muß eine effektive, verlustfreie Probenaufbereitung sichergestellt werden. Während bei der Verarbeitung einfacher sowie terpenarmer (entterpenisierter) Orangenöle keine Isotopendiskriminierung auftritt, sind bei Spezialprodukten, bei denen einzelne Substanzen Konzentrationen von >70% erreichen, Abweichungen des13C/12C-Isotopenverhältnisses feststellbar.
The influence of analytical and technological procedures on the13C/12C isotope ratio of orange oil compounds
The influence of Chromatographic and technological procedures on the13C-isotope value of flavour compounds from orange oils was investigated. In order to avoid misinterpretations of isotopic data, quantitative yields during sample clean-up must be ascertained. Ordinary as well as deterpenated orange oils were not influenced by the technological processing. In the case of special products containing single compounds concentrated up to more than 70%, a shift in the13C/12C-isotope ratio was detectable.相似文献