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81.
Jan Meiss Markus HummertAnnette Petrich Steffen PfuetznerKarl Leo Moritz Riede 《Solar Energy Materials & Solar Cells》2011,95(2):630-635
We present the material 2,3,10,11-tetrabutyl-1,4,9,12-tetraphenyl-diindeno[1,2,3-cd:1′,2′,3′-lm] perylene (Bu4-Ph4-DIP) as alternative green donor for bulk heterojunction small molecule organic solar cells (SMOSC). It is shown that Bu4-Ph4-DIP exhibits suitable absorption characteristics to be a potential material to fill the absorption gap between the commonly used standard absorbers ZnPc and C60.Devices with bulk heterojunctions of Bu4-Ph4-DIP:C60 display very high open circuit voltages of 0.99 V, high fill factors of up to 57%, and experiments yield promising efficiencies of η>2%. Such green-blue absorbing SMOSC are characterized by current voltage and external quantum efficiency measurements, and material properties are studied. It is shown that the devices are responsive to substrate heating, and that different donor-acceptor mixing ratios can increase device performance. Possible influences of mixing ratio and heating on device morphology and electrical properties are discussed. 相似文献
82.
83.
The Effect of Gradual Fluorination on the Properties of FnZnPc Thin Films and FnZnPc/C60 Bilayer Photovoltaic Cells
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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
84.
This introduces an organic–inorganic thermosetting hybrid resin system based on unsaturated polyester and polysilazanes. It shows the chemical modification of unsaturated polyester structures by end capping to enable the combination of both components. In general, halogen‐free unsaturated polyesters are not fire‐retardant and have to be equipped with additives. Fillers and intumescent additives are preponderantly used in today's fire‐retardant formulations. In contrast to these fire‐retardants, polysilazanes act as ceramizing agents. Polysilazanes are suitable fire‐retardants for resin transfer molding due to their low viscosity. Both burning behavior and glass transition temperature (Tg) are investigated as important application properties. In contrast to state‐of‐the‐art fire‐retardant formulations polysilazane‐based thermosetting hybrid resins burn with high intensity and fast extinction. Therefore, total heat and smoke emission is decreased. The formation of ceramic structures during burning results in high residual mechanical properties and a low mass loss. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40375. 相似文献
85.
Partial oxidation of methane in hollow‐fiber membrane reactors based on alkaline‐earth metal‐free CO2‐tolerant oxide
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Yanying Wei Qing Liao Zhong Li Haihui Wang Armin Feldhoff Juergen Caro 《American Institute of Chemical Engineers》2014,60(10):3587-3595
The U‐shaped alkaline‐earth metal‐free CO2‐stable oxide hollow‐fiber membranes based on (Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ (PLNCG) are prepared by a phase‐inversion spinning process and applied successfully in the partial oxidation of methane (POM) to syngas. The effects of temperature, CH4 concentration and flow rate of the feed air on CH4 conversion, CO selectivity, H2/CO ratio, and oxygen permeation flux through the PLNCG hollow‐fiber membrane are investigated in detail. The oxygen permeation flux arrives at approximately 10.5 mL/min cm2 and the CO selectivity is higher than 99.5% with a CH4 conversion of 97.0% and a H2/CO ratio of 1.8 during 140 h steady operation. The spent hollow‐fiber membrane still maintains a dense microstructure and the Ruddlesden‐Popper K2NiF4‐type structure, which indicates that the U‐shaped alkaline‐earth metal‐free CO2‐tolerant PLNCG hollow‐fiber membrane reactor can be steadily operated for POM to syngas with good performance. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3587–3595, 2014 相似文献
86.
Chemikalienfreie Bekämpfung von Holzschädlingen durch dielektrische Erwärmung mit Radiowellen und Mikrowellen
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Christian Hoyer Christian Pfütze Dr. Rudy Plarre Dr. Ulf Trommler Steffen Steinbach Kerstin Klutzny Dr. Frank Holzer Carsten Rabe Björn Höhlig Prof. Frank‐Dieter Kopinke Prof. Detlef Schmidt Dr. Ulf Roland 《化学,工程师,技术》2014,86(8):1187-1197
Thermal pest control requires long treatment times due to the low thermal conductivity of wood and may lead to the formation of cracks. Here, the thermal treatment with radio waves as well as microwaves has been studied. The direct dielectric heating has the advantage of a good homogeneity. The obtained temperature profiles for radio waves were more homogeneous compared to microwaves. Detailed studies showed that elimination of pests was not related to the application of the electromagnetic field itself, but due to the temperature increase. 相似文献
87.
Sandra Schlögl Marie-Luise Trutschel Walter Chassé Ilse Letofsky-Papst Raimund Schaller Armin Holzner Gisbert Riess Wolfgang Kern Kay Saalwächter 《Polymer》2014
The photo-vulcanization with versatile thiol-ene chemistry represents an innovative approach to crosslink diene-rubber materials both in latex and in solid film state. In this work, the structure of elastomer-based thiol-ene networks and the morphology after film formation are studied in detail using electron microscopic techniques, atomic force microscopy and multiple-quantum solid-state NMR spectroscopy. Additionally, film formation properties and corresponding macroscopic properties of photo-vulcanized natural rubber (NR) latex and its synthetic counterpart, isoprene rubber (IR) latex, are determined in dependence on the curing procedure (pre- and post-vulcanization). The results reveal that thiol-ene cured elastomers comprise homogenously distributed crosslinks with a low amount of short chain defects. Whilst photochemically pre-cured NR latex particles provide coherent films, the film formation and mechanical properties of IR are strongly governed by the crosslink density of the latex particles. In film state, photo-vulcanization promotes narrow crosslink distributions and excellent tensile properties of both NR and IR. 相似文献
88.
Ramona Erber Steffen Spoerl Andreas Mamilos Rosemarie Krupar Arndt Hartmann Matthias Ruebner Juergen Taxis Mareike Wittenberg Torsten E. Reichert Gerrit Spanier Silvia Spoerl 《International journal of molecular sciences》2022,23(1)
Oral cancer often presents with aggressive behavior and a high risk of recurrence and metastasis. For oral squamous cell carcinoma (OSCC), which is the most frequent histological subtype, therapy strategies include surgery, radiation therapy, chemotherapy, immune checkpoint inhibitors, and EGFR inhibitors. Recently, a Trop-2 antibody-drug conjugate (ADC) has been approved in the United States of America for the treatment of advanced triple-negative breast cancer. However, this ADC has also been tested in other solid tumors including head & neck squamous cell carcinoma. The prognostic impact of Trop-2 has already been reported for several cancers. We studied the prognostic influence of Trop-2 protein expression on OSCC patients’ survival. The cohort comprised n = 229 OSCC patients with available archived tumor tissue and corresponding non-neoplastic oral mucosa tissue. Using immunohistochemistry, we investigated Trop-2 expression in both the central and peripheral regions of each tumor and in corresponding non-neoplastic oral mucosa. In patients suffering from OSCC with combined high central and low peripheral Trop-2 expression, five-year overall survival (OS) was 41.2%, whereas 55.6% of OSCC patients who presented lower central and/or higher peripheral tumoral Trop-2 expression were alive after five years (p = 0.075). In multivariate Cox regression, the expression pattern of high central tumoral and lower peripheral Trop-2 expression was significantly correlated with impaired OS (HR = 1.802, 95%-CI: 1.134–2.864; p = 0.013) and recurrence-free survival (RFS) (HR = 1.633, 95%-CI: 1.042–2.560; p = 0.033), respectively, when adjusting for co-variables. Hence, Trop-2 may serve as an independent prognostic biomarker in OSCC. In subsequent studies, the pathophysiological meaning of downregulated Trop-2 expression in the OSCC periphery has to be analyzed. 相似文献
89.
Letícia Helena Gasparini Paes Teresa Tromm Steffen Daniela Becker 《Polymer Engineering and Science》2020,60(6):1333-1342
Multiwall carbon nanotubes (CNT) or montmorillonite clay (MMT-30B) were added to a poly(hexamethylene isophthalamide-co-terephthalamine) (an amorphous polyamide - aPA) and styrene-ethylene/butylene-styrene graphitized with maleic anhydride (SEBS) blend, in different concentrations, in order to investigate the morphology, thermal properties and flammability behavior. Different nanoparticle localizations in the phase blend were observed through transmission electronic microscopy. CNT nanoparticles are localized in SEBS phase, and MMT-30B nanoparticles in aPA phase. No significant changes were observed on transition temperatures and thermal stability with both nanoparticle additions. However, a slight increase on storage modulus for clay nanocomposites and a slight reduction for carbon nanotube nanocomposites were observed, due to their different phase localizations. Regarding flammability, CNT nanocomposites showed better performance as a flame retardant when compared to samples with MMT-30B. Although the MMT-30B nanocomposites could not be classified according to the UL-94 criteria, no dripped flaming particles were observed, due to the a char barrier formation on the polymer surface. The CNT nanocomposites were classified according to the UL-94 criteria as V-2. The CNT's selective localization on the SEBS phase decreases its heat-release rate, but no interconnected network structure was formed in the matrix to suppress the dripping flaming particles. 相似文献
90.
Steffen A Schroeder W Macdonald R Poissant L Konoplev A 《The Science of the total environment》2005,342(1-3):185-198
Eight years of gaseous elemental mercury (GEM) concentration measurements from Alert, Nunavut, Canada (between 1995 and 2002) is presented. The annual time series shows a distinct repeating seasonal pattern with an overall annual median concentration for this time period of 1.58 (S.D.=0.04 ng m(-3)). Strong seasonal variation was observed throughout the years with springtime displaying strong variability in the GEM and overall lower median concentrations due to the so-called mercury depletion events (MDEs). Summer concentrations are higher than the annual average and show a decrease in variability. Fall and winter concentrations are distributed around the annual median concentrations and show little variability. The relationship between the springtime depression and the summer increase shows a change in the behaviour of mercury between 1995 and 2002. Preliminary results suggest that during this period an increasing amount of the mercury lost from the atmosphere in the spring is not returned to atmosphere in summer. A comparison of GEM concentration data from three sites--Alert (Canada), Amderma (Russia) and Kuujjuarapik (Canada)--demonstrated similar monthly distribution of GEM between Alert and Amderma, with the latter not showing as high summer concentrations. Monthly distribution of GEM at Kuujjuarapik varied considerably from the other two sites. MDEs were found to occur at each site in the spring yet displayed different characteristics. MDEs appear to start at Alert shortly after polar sunrise but in Amderma their initiation is delayed approximately 2 months following polar sunrise. MDEs occur in Kuujjuarapik in the springtime despite an incomplete development of the polar day-night cycle. In spring, as soon as air temperature attained temperatures consistently above 0 degrees C, MDEs ended immediately at all three sites. Continued studies into MDEs are warranted, but clearly an important component of future studies must focus on the origins of the variation of GEM behaviour at different sites. 相似文献