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121.
The effects of size and shape of austenite grains on the extraordinary hardening of steels with transformation induced plasticity (TRIP) have been studied. The deformation and transformation of austenite was followed by interrupted ex situ bending tests using electron backscatter diffraction (EBSD) in a scanning electron microscope (SEM). A finite element model (FEM) was used to relate the EBSD based results obtained in the bending experiments to the hardening behavior obtained from tensile experiments. The results are interpreted using a simple rule of mixture for stress partitioning and a short fiber reinforced composite model. It is found that both, the martensite transformation rate and the flow stress difference between austenite and martensite significantly influence the hardening rate. At the initial stage of deformation mainly larger grains deform, however, they do not reach the same strain level as the smaller grains because they transform into martensite at an early stage of deformation. A composite model was used to investigate the effect of grain shape on load partitioning. The results of the composite model show that higher stresses develop in more elongated grains. These grains tend to transform earlier as it is confirmed by the EBSD observations. 相似文献
122.
Vuchinich Rudy; Wallace Dennis; Milby Jesse B.; Schumacher Joseph E.; Mennemeyer Stephen; Kertesz Stefan 《Canadian Metallurgical Quarterly》2009,17(3):165
Clinical trials with cocaine-dependent outpatients have found a strong relation between in-treatment and follow-up abstinence, and the strength of this relation is constant across treatment conditions with variable efficacy in generating abstinence. The authors conducted secondary analyses of data from 3 clinical trials to determine whether this relation generalizes to cocaine-dependent homeless persons. The 3 trials (total N = 543) were conducted in a community health care facility for homeless people. The 7 treatment arms across the 3 trials were combinations of day treatment, abstinence-contingent housing, and vocational training. Drug use was measured with urine toxicology testing. Consecutive weeks of abstinence during treatment were strongly related to abstinence at the 12-month follow-up, whether or not missing 12-month data were included in the analysis. The treatment arms differed in their efficacy in generating abstinence, but the relation between in-treatment and follow-up abstinence did not differ across treatment arms. These results replicate earlier reports of these relations and extend them to a population of homeless people. The lack of differences between treatment arms in the in-treatment–follow-up abstinence relation implies that that relation is independent of the treatment-specific intervention components that generate group differences in abstinence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
123.
Bulky End‐Capped [1]Benzothieno[3,2‐b]benzothiophenes: Reaching High‐Mobility Organic Semiconductors by Fine Tuning of the Crystalline Solid‐State Order 下载免费PDF全文
Guillaume Schweicher Vincent Lemaur Claude Niebel Christian Ruzié Ying Diao Osamu Goto Wen‐Ya Lee Yeongin Kim Jean‐Baptiste Arlin Jolanta Karpinska Alan R. Kennedy Sean R. Parkin Yoann Olivier Stefan C. B. Mannsfeld Jérôme Cornil Yves H. Geerts Zhenan Bao 《Advanced materials (Deerfield Beach, Fla.)》2015,27(19):3066-3072
124.
Prof. Dr. Andreas Leson Gregor Englberger Daniel Hammer Stefan Makowski Carl‐Friedrich Meyer Michael Leonhard Hans‐Joachim Scheibe Volker Weihnacht 《真空研究与实践》2015,27(4):24-28
Diamond‐like carbon thin films enhance efficiency — laser arc deposition of ta‐C Rising prices for fossil fuels as well as the increasing effects of the climate change due to the emission of greenhouse gases reveal the necessity of saving energy. Low friction coatings have an enormous potential in saving energy. Carbon based coatings — named as DLC coatings — are especially well suited for low friction coatings. In particular hydrogen‐free tetrahedral amorphous carbon (ta‐C) coatings are of great interest due to their extraordinary low wear properties. In addition they show excellent low friction properties and especially in combination with specific lubricants the so‐called super low friction effect. For the deposition of ta‐C coatings PVD methods have to be applied instead of CVD methods as it is the case for conventional DLC coatings. We have developed a deposition method which is based on a pulsed arc steered by a laser (Laser‐Arc). This allows us to use large cathodes resulting in a high long‐term stability. Furthermore, the carbon plasma source can be combined with a filtering unit removing almost all droplets and particles, which usually are characteristic for an arc process. The resulting Laser‐Arc source allows for the deposition of smooth and virtually defect‐free ta‐C coatings with a competitive deposition rate. 相似文献
125.
The Effect of Gradual Fluorination on the Properties of FnZnPc Thin Films and FnZnPc/C60 Bilayer Photovoltaic Cells 下载免费PDF全文
Michael Brendel Stefan Krause Andreas Steindamm Anna Katharina Topczak Sudhakar Sundarraj Peter Erk Steffen Höhla Norbert Fruehauf Norbert Koch Jens Pflaum 《Advanced functional materials》2015,25(10):1565-1573
Motivated by the possibility of modifying energy levels of a molecule without substantially changing its band gap, the impact of gradual fluorination on the optical and structural properties of zinc phthalocyanine (FnZnPc) thin films and the electronic characteristics of FnZnPc/C60 (n = 0, 4, 8, 16) bilayer cells is investigated. UV–vis measurements reveal similar Q‐ and B‐band absorption of FnZnPc thin films with n = 0, 4, 8, whereas for F16ZnPc a different absorption pattern is detected. A correlation between structure and electronic transport is deduced. For F4ZnPc/C60 cells, the enhanced long range order supports fill factors of 55% and an increase of the short circuit current density by 18%, compared to ZnPc/C60. As a parameter being sensitive to the organic/organic interface energetics, the open circuit voltage is analyzed. An enhancement of this quantity by 27% and 50% is detected for F4ZnPc‐ and F8ZnPc‐based devices, respectively, and is attributed to an increase of the quasi‐Fermi level splitting at the donor/acceptor interface. In contrast, for F16ZnPc/C60 a decrease of the open circuit voltage is observed. Complementary photoelectron spectroscopy, external quantum efficiency, and photoluminescence measurements reveal a different working principle, which is ascribed to the particular energy level alignment at the interface of the photoactive materials. 相似文献
126.
127.
Stefan M. Holzer 《Bautechnik》2015,92(3):230-237
128.
Functionalized galactoglucomannan‐based hydrogels for the removal of metal cations from aqueous solutions 下载免费PDF全文
Elizabeth Elgueta Julio Sánchez Daniel Dax Chunlin Xu Stefan Willför Bernabé L Rivas Marianela González 《应用聚合物科学杂志》2016,133(41)
New types of hydrogels derived from O‐acetyl galactoglucomannan (AcGGM) hemicellulose have been synthesized and characterized. The objective of this work was to analyze the sorption capacity (S) of three types of hydrogels containing AcGGM derivatives incorporated into the carboxylic groups of the polymer chain in the AA hydrogel, sulfonic groups in the APA hydrogel, and amide groups in the acrylamide (Aam) hydrogel. These hydrogels are capable of interacting and removing ions such as cadmium [Cd(II)], copper [Cu(II)], lead [Pb(II)], nickel [Ni(II)], and zinc [Zn(II)]. The results show that AA and Aam hydrogels had a lower sorption capacity of ions compared to the APA hydrogel, which had a high sorption capacity. The maximal sorption capacity was determined by the successive enrichment method, obtaining Pb(II) amount of 48.3 mg/g of AA hydrogel, 65.8 mg/g of APA hydrogel, and 40.8 mg/g of Aam hydrogel. Hence, Pb(II) ions are greatly retained by the three hydrogels. These results are promising for the development of new materials with potential applications in metal ion removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44093. 相似文献
129.
Wolfram Witte Daniel Abou‐Ras Karsten Albe Gottfried H. Bauer Frank Bertram Christian Boit Rudolf Brüggemann Jürgen Christen Jens Dietrich Axel Eicke Dimitrios Hariskos Matthias Maiberg Roland Mainz Max Meessen Mathias Müller Oliver Neumann Thomas Orgis Stefan Paetel Johan Pohl Humberto Rodriguez‐Alvarez Roland Scheer Hans‐Werner Schock Thomas Unold Alfons Weber Michael Powalla 《Progress in Photovoltaics: Research and Applications》2015,23(6):717-733
The gallium gradient in Cu(In,Ga)Se2 (CIGS) layers, which forms during the two industrially relevant deposition routes, the sequential and co‐evaporation processes, plays a key role in the device performance of CIGS thin‐film modules. In this contribution, we present a comprehensive study on the formation, nature, and consequences of gallium gradients in CIGS solar cells. The formation of gallium gradients is analyzed in real time during a rapid selenization process by in situ X‐ray measurements. In addition, the gallium grading of a CIGS layer grown with an in‐line co‐evaporation process is analyzed by means of depth profiling with mass spectrometry. This gallium gradient of a real solar cell served as input data for device simulations. Depth‐dependent occurrence of lateral inhomogeneities on the µm scale in CIGS deposited by the co‐evaporation process was investigated by highly spatially resolved luminescence measurements on etched CIGS samples, which revealed a dependence of the optical bandgap, the quasi‐Fermi level splitting, transition levels, and the vertical gallium gradient. Transmission electron microscopy analyses of CIGS cross‐sections point to a difference in gallium content in the near surface region of neighboring grains. Migration barriers for a copper‐vacancy‐mediated indium and gallium diffusion in CuInSe2 and CuGaSe2 were calculated using density functional theory. The migration barrier for the InCu antisite in CuGaSe2 is significantly lower compared with the GaCu antisite in CuInSe2, which is in accordance with the experimentally observed Ga gradients in CIGS layers grown by co‐evaporation and selenization processes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
130.
Britta Schning Wolfgang H Ziegler Stefan Vieths Werner Baltes 《Journal of the science of food and agriculture》1996,71(4):475-482
Considering the known N-terminal amino acid sequence of the major apple allergen, a polymerase chain reaction (PCR) primer was selected to amplify cDNA encoding this protein. A single PCR product was obtained, cloned into Escherichia coli and subsequently sequenced. The missing 5′-end of the apple cDNA sequence was obtained by a 5′-RACE method. The cDNA sequence showed 72% identity with the coding region of one of the known isoforms of Bet v 1, the major allergen of birch pollen. The deduced amino acid sequence resulted in a 158-residue protein with a calculated molecular mass of 17·5 kDa and 63% amino acid sequence identity to Bet v 1. In addition, further protein alignments showed a high degree of identity with allergens from other tree pollens and some ‘pathogenesis-related proteins’ from food plants. According to international regulations the allergen was termed Mal d 1 for this protein, it being the first major allergen discovered and characterised in fruits of apple (Malus domestica). 相似文献